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+RustyNES **v2.4.1 "Fabric"** opens the **v2.4.1 → v2.5.0 "Fabric"** line: a new NES core written in SystemVerilog from public hardware documentation, in a sibling repository, with this emulator as its **verification oracle**. The line is named for what it builds — and RustyNES's role in it is the warp: the fixed threads held under tension that everything else is woven against. That is the one role this emulator is uniquely equipped for.
+
+**It also ships v2.4.0 "Concordance", which never received its own tag.** That work merged to `main` and the release was never cut, so this release carries both. Where a section below belongs to v2.4.0 it says so.
+
+**The accuracy contract is verified, not asserted.** `rustynes-core` changes in both halves, so AccuracyCoin was re-run rather than reasoned about: **141/141 (100.00%)** on the authoritative RAM decoder, nestest 0-diff. The framebuffer decoder reports 120 and remains known-buggy.
+
+## RustyNES is not being ported to FPGA, and cannot be
+
+A MiSTer core is SystemVerilog compiled by Quartus 17.0.2 into a Cyclone V bitstream. Rust does not become a bitstream, and high-level synthesis of a cycle-accurate emulator's control flow does not produce usable hardware. What is buildable is a **new implementation** verified against this one, and `crates/rustynes-cosim` is the boundary between them: a narrow C ABI a Verilator testbench links, plus the safe Rust API a golden-export binary uses.
+
+The reference firewall extends to HDL accordingly. `NES_MiSTer` and `fpganes` `rtl/` are **strict black boxes** — instantiable as opaque modules to compare *outputs*, never readable as source. Anything unimplementable from documentation escalates to an ADR **before** any source is opened.
+
+**Replay, not lockstep**, because `Nes` exposes `run_frame()` and `step_instruction()` and nothing finer. Cycle-lockstep would mean new core API on the hot path and would gain nothing: the determinism contract already makes a pre-recorded trace *exactly* the trace a lockstep run produces. **No DPI-C**, because it puts `` `ifdef SIMULATION `` guards into RTL that must also pass Quartus — the construct that lets a simulated netlist drift from the synthesised one. **Hash first, capture on divergence**, because a 4200-frame AccuracyCoin run is ~125 M cycles, which as per-cycle CSV is ~7.5 GB against 244 KB of 4096-cycle checkpoints.
+
+The golden framebuffer is exported **pre-palette** so a palette difference cannot masquerade as a rendering difference — the failure mode v2.3.8 "Parallax" was built to prevent.
+
+**v2.5.0 is scoped to "the 6502 rung closes"**, not a finished core. A from-scratch cycle-accurate NES core is 7–13 months FTE; PPU, APU and MiSTer integration are the v2.6–v2.9 programme. Two risks are accepted in writing: `NES_MiSTer` scores 121/125 on AccuracyCoin where *real Famicom AV hardware also scores ~121/125*, so there is no published accuracy headroom and the core **may be declined as a duplicate**; and **the oracle can be wrong**, since 141/141 is not "matches silicon". Every rung is labelled by whether it has an *independent* oracle. Full reasoning: ADR 0037, `docs/mister.md`, `to-dos/plans/v2.5.0-fabric-plan.md`.
+
+## The first `run_frame()` after power-on advances zero cycles
+
+The PPU is constructed at dot 340 of the pre-render line, so the seven-cycle reset sequence ticks past the frame wrap and leaves `frame_complete` latched. The first call consumes that latch and returns having stepped nothing. Measured, not inferred: frame 0 advances the cycle counter by **0**, frames 1..3 by ~29,780 each.
+
+Every existing caller runs thousands of frames, so one lost frame is invisible to them. It stops being invisible the moment a **count** is recorded beside the output — `--frames 60` through a bare loop emits a 59-frame golden under a manifest claiming 60, which is a provenance record wrong in the one direction that matters. `Oracle::advance_frames` gates on the frame **counter**, with a jam bail-out, and the quirk is pinned by a test that names it.
+
+## The accuracy battery was validating a scheduler no user runs
+
+The most serious finding in the release, and it was found by review rather than by a gate.
+
+`rustynes-cosim` enables `cpu-boot-trace` and `irq-timing-trace` on `rustynes-core`, and cargo unifies features across a workspace build. As a workspace member it made `cargo build --workspace` compile the core **once** with the union — measured through `--message-format=json`, not inferred:
+
+```text
+['cpu-boot-trace', 'debug-hooks', 'default', 'hd-pack', 'irq-timing-trace', 'std']
+```
+
+`irq-timing-trace` is not an inert branch: it selects a **different** `for sub_dot in 0..3` loop in `Bus::tick_one_cpu_cycle`. There are two, under opposite `cfg`s. So CI's `cargo test --workspace --release --features test-roms` — the accuracy battery — was validating the instrumented scheduler rather than the shipped one. The same shape as the v2.3.4 defect where the coverage harness tested a load path no user runs.
+
+**The measured cost was +1.24% / +1.39% / +1.89%** across the three `full_frame` benches, *below* this project's own 3% adoption bar, and it never touched the shipped binary (`-p rustynes-frontend` does not select this crate) or the perf gate (`cargo bench -p rustynes-core`). That number is published precisely because it shows performance was never the argument. A gate pointed at the wrong code path is wrong at any percentage.
+
+The crate is now in `[workspace] exclude`. Both costs of that are closed mechanically rather than trusted: `cosim_manifest_audit.rs` asserts every duplicated field and lint still equals the workspace's **and** that the crate is still excluded — four mutations, all caught — and CI gains explicit `fmt`, `clippy` and `test` steps, since `--all`/`--workspace` no longer reach it. The clippy step earned its place on its first run, reporting a `must_use_candidate` that `--workspace` had never surfaced.
+
+## Every path that persists user data now writes atomically and durably (v2.4.0)
+
+The seven-property write sequence v2.3.9 built for `Config::save_to` is extracted into `crate::atomic_write` and adopted everywhere. The plan named three call sites; there were **four**, and the fourth is the instructive one.
+
+`save_state.rs` matters most and was named last: **a truncated save state is a user's game progress**, a worse loss than a truncated config, and it was still using the bare `fs::write` the config path had already been fixed for. It is also the path most likely to be written under load — rewind capture, run-ahead and netplay rollback all produce save states.
+
+`per_game.rs` was not in the plan at all, because it *looks* correct: it writes a sibling temp file and renames, so a sweep for `fs::write`-onto-a-target clears it. It held two of seven. No `fsync`, so the rename could commit a directory entry pointing at bytes that never reached the medium; and a **fixed** scratch name shared across every process and concurrent call — the exact failure the mechanism exists to prevent, reintroduced by the mechanism. A partially-correct implementation is harder to spot than an absent one.
+
+Review then found **four more places the module reported success it had not earned**, each with the same shape — an error discarded under a comment explaining the rest of the operation:
+
+- **`set_permissions` swallowed.** The mode applied is the mode the target *already had*, so a failure replaces a `0600` file with one at the umask default — **wider than what it replaced** — and reports success.
+- **The parent-directory `fsync` swallowed**, along with the `File::open` feeding it, so the entire durability barrier could be a no-op while the module's own table claimed "yes". `EIO` — the exact condition it exists to detect — passed as success. It now propagates, excepting only the errnos that mean *this filesystem has no barrier* (`EINVAL`, `ENOTSUP`/`EOPNOTSUPP`, and `EBADF` on some network mounts).
+- **The occupied-scratch retry was one attempt**, justified by "the counter cannot repeat a name within a process" — true, and beside the point, because the collision comes from a *previous* process whose pid was reused. Now a bounded loop.
+- **On exhaustion, the cleanup deleted a file this process had not created** — an orphan, or a scratch file a colliding instance was actively writing. A failed save took another process's in-progress data with it.
+
+**A `const fn` that only failed on Windows.** `is_transient_rename_error` was `const` and called `io::Error::kind`, which is not — `E0015`, behind `#[cfg(windows)]`, so it compiled clean on Linux. PR runs here are Linux-only and the full matrix runs on `main`, so it would have turned `main` red *after* merge. The fix is not just dropping `const`: the predicate moved into an always-compiled function reached through `cfg!(windows) && …`, so restoring the `const` now fails **on Linux** with the same error. The defect class moved from "invisible until another platform builds it" to "fails the PR".
+
+Also here: the cheat save reports its failure in the panel instead of printing to a `stderr` nobody reads on a windowed build; symlink chains resolve to their end, bounded at Linux's own `MAXSYMLINKS` of 40; and the rename retry budget outlasts a Windows Defender scan lock — adopted on an **unverified** timing claim, recorded as unverified, because the cost is a longer stall on a save that is already failing.
+
+## A timeline generation counter, and the telemetry that reads it (v2.4.0)
+
+v2.3.9 cleared stale debug telemetry on a ROM change and recorded that it could not clear it on a save-state load: of the four ways the emulator jumps timeline, only one is reachable from a patchable frontend call site. `Nes::timeline_generation()` is a session-local counter that any consumer can compare against its last-seen value — and it can see a restore to a *later* state, which the previous last-seen-`cycle()` heuristic could not.
+
+It is **not** part of the save state, and the reasoning is now on the field with a test pinning it. Serializing it would break two things silently: loading the same slot twice would restore the same generation twice, so a consumer would miss the second load; and a value from another session means nothing in this one. Because it lives outside the snapshot, `snapshot_schema_audit` cannot see it — the property that makes the design correct also means nothing mechanical would notice the reasoning being invalidated.
+
+## Release anchors, and a claim v2.3.9 made that v2.3.9 did not ship
+
+`release_anchor_audit.rs` pins **15 anchors across 10 documents** against `[workspace.package] version`, fails closed when a marker matches nothing, and asserts the CHANGELOG header parses the way `release-auto.yml` parses it.
+
+It is described in **v2.3.9's release notes and is not in the v2.3.9 tag.** It merged in #427, after the tag was cut. The audit exists because eight documents had reached six different answers about the current version; that a release note could describe work the release does not contain is the same failure one level up, and it ships here.
+
+## Under the surface
+
+- **The review bot destroyed its own record.** It posted a fresh comment each round and deleted the previous one, so a round nobody read before the next push was gone with nothing indicating it had existed — observed on PR #428, where two consecutive rounds each raised a blocking issue, one a data-loss defect, and only the second survived. It now edits one comment per PR, folding earlier rounds into a bounded, sentinel-delimited archive, and issues no `DELETE` at all.
+- **A dot in a ROM name truncated every golden filename.** `Path::with_extension` replaces after the *last* dot, so `Super Mario Bros. 3` yielded `Super Mario Bros.ram.bin`. NES filenames contain dots routinely.
+- **No CI invocation had ever enabled `cpu-boot-trace` or `irq-timing-trace` for clippy**, so those two `rustynes-core` modules had never passed the lint gate. Six pre-existing findings, all fixed. `--workspace --all-targets` reads as exhaustive and covers each crate's *default* feature set only.
+- **The rung-0 gate is shown able to fail**, not merely to pass: the null-DUT self-diff reports `All 5464 aligned records match` and exits 0, and a one-bit corruption is caught at cycle 561, PC `$C419`, naming the field and both values.
+- **`actions/checkout` is SHA-pinned** on the self-hosted reviewer runner — the maintainer's own machine, where a compromised tag executes rather than in a disposable VM.
+- Empty `hd_packs` / `shader_presets` tables no longer write into an untouched config, correcting a false byte-identity claim v2.3.9 had corrected in prose only.
+
+## Verification
+
+- **AccuracyCoin 141/141 (100.00%, RAM decoder)** and **nestest 0-diff**, re-run on the shipped path after the workspace exclusion rather than reasoned about.
+- **129 test suites, 2236 tests, 0 failures** — 126 suites / 2222 in the workspace plus the excluded crate's 3 / 14, which CI runs explicitly.
+- Full gate matrix: `fmt`, workspace clippy, the four frontend feature combinations, **both** wasm32 combinations, the `no_std` thumbv7em build, and rustdoc with warnings as errors.
+- Every new assertion in this release was demonstrated to fail by mutation before being trusted — including one caught only as a **hang**, and one whose first mutation pass was rejected because the mutants had failed to *compile*, which proves nothing.
+
+## Upgrade notes
+
+No format epochs change. Save states (`.rns`), movies (`.rnm`) and netplay replays are unchanged from v2.3.9, and the shipped emulation core is byte-identical on the default configuration. `crates/rustynes-cosim` is additive, outside the default build, and cannot be reached by an ordinary `cargo build`.
diff --git a/AGENTS.md b/AGENTS.md
index 39005911..07f9899e 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -41,7 +41,7 @@ Enforcement lives alongside the prose: `/ref-proj/` is gitignored/`.dockerignore
 
 RustyNES is a cycle-accurate Nintendo Entertainment System emulator written in pure Rust. The accuracy bar is Mesen2 / higan / ares: tight lockstep scheduling at PPU-dot resolution on a master-clock-precise timebase, sub-instruction PPU events visible to subsequent CPU code, and a lookup-table non-linear audio mixer with band-limited synthesis. The frontend is pure Rust (`winit` + `wgpu` + `cpal` + `egui`).
 
-**Current release: v2.3.9 "Crucible"** (2026-08-20) — the **gates** release. A crucible tests something to destruction rather than inspecting it, and that is what this release does to the project's own checks: what they cover, what they only *appear* to cover, and where a regression could still reach `main` unchallenged. The v2.3.x line added five tools in four releases and the recurring finding across all of them was never that the emulation was wrong — it was that **a check reported a pass it had not earned**. **The docs-only CI skip had never worked**: `dorny/paths-filter`'s `predicate-quantifier` defaults to `some`, which includes a file if it matches ANY pattern, so the `code` filter's leading `'**'` matched everything and all seven `!` exclusions under it were DEAD from the day they were written — proven from a run rather than the docs (a one-file markdown PR logged `Filter code = true` / `Matching files: AGENTS.md`). Every documentation PR in the project's history had been running the full matrix, and that stopped being merely wasteful the day two docs-only PRs were *blocked* by an ARM cross-compile failure on jobs that should never have been scheduled. Fixed with **two** filter steps because the quantifier is step-level and the two filters need OPPOSITE settings: `code` needs `every`, while `accuracy` is a list of **alternatives** and becomes unsatisfiable under it — the naive one-line fix would have silently disabled the accuracy battery while repairing a different gate. Both directions are now observed on real PRs. **The accuracy battery now runs at review time** — `test-roms` was full-run-only, so a regression landed on `main` rather than on the PR that caused it; it is now also path-filtered over the chip crates, the core, `rustynes-gamedb` (it rewrites the iNES header on load, so it changes what the emulator *is* before a cycle runs), the harness and `tests/`, measured first at 11 of the last 40 merged PRs so ~72% still pay nothing. **Bounds were calibrated against a measurement rather than a claim**: the ARM provisioning step failed on three consecutive PRs with NO apt error in the log at all, and the real number was `Fetched 4201 kB in 4min 45s (14.7 kB/s)` — three orders of magnitude below normal, which made the previous ~40 MB package set *hopeless* rather than unlucky (~45 minutes; no timeout could have saved it); it was also installing a whole cross toolchain to obtain `libc6-dev-<arch>-cross`, which the comment above it had already named, because bindgen runs the **host** clang against `--sysroot` and never invokes the cross compiler. **A freeze from one cartridge kept writing into the next** — not a stale label but an active per-frame write into the wrong game, because both memory panels' freezes feed the raw-cheat overlay applied after every frame and neither was registered with the ROM-transition hook; the sweep that closed it now covers every panel under ONE rule: **derived output is discarded, user-authored input is kept, and only input that actively *writes* is neutralised** (so RAM Search baselines and reconstructed call stacks clear, while watch lists and breakpoints survive and breakpoints stay ARMED — a breakpoint halts, visible and recoverable, where a freeze writes, silent and continuous). Two negatives are recorded because they cost time to establish: the header editor LOOKS ROM-bound and is not (it is a standalone file tool), and the event panel / trace status / HD-pixel coordinates are per-frame state or preferences. **The config file is written atomically and durably** — `fs::write` truncates then writes, and saves became automatic (closing a ROM, moving a mixer slider, finishing a Latency Oracle measurement), so an interruption left the user holding a truncated `config.toml`; seven properties, and **five came from review rather than the first draft** (sibling scratch file, `fsync` before rename, parent-directory sync, `create_new(true)` for CWE-377, mode applied at creation, symlink resolution including a **broken** link, and a pid + per-call counter — the last is what makes exclusive creation adoptable at all). **Two shipped features told the truth for the first time**: movies record TWO ports (`FrameInput` models P1 and P2) while the Replay panel printed "Four Score (P1..P4)" at the moment a user decides to press Record — widening the format is a `.rnm` epoch change, so it is disclosed at three levels with the caveat printed directly under the claim it qualifies; and a failed Latency Oracle save now says so instead of being swallowed (remembering is still NOT applying — nothing touches `run_ahead`, and an inconclusive result is not remembered at all). Also: **257 lines of dead code removed** — an APU pair (34), a closed `LockstepBus` DMA-service island (183), and `drain_dma` (40), a function called on every CPU read, every CPU write and every bus cycle whose entire body was `let _ = read_addr;` and whose comments claimed the legacy service below it "stays active for the default build" — alongside **25 of 29 `#[allow(dead_code)]` attributes suppressing nothing**, established by stripping them and re-running clippy across all EIGHT gated combinations (an item can be live by default and dead on wasm, which is precisely the case that would have earned the attribute); the **SAFETY-comment rule is now a gate** (`clippy::undocumented_unsafe_blocks` — all 91 unsafe sites already carried a justification, two had it where a human reads correctly and a checker cannot, and the lint is demonstrated to fail); and two `cargo deny` advisory ignores retired on their own stated condition (their entry said to remove them once the resolve moved past quick-xml 0.40, and it had). `rustynes-apu` and `rustynes-core` both change, so **AccuracyCoin 141/141 (100.00%, RAM decoder) and nestest 0-diff are VERIFIED, not asserted** — and re-run AGAIN after the second round of deletions rather than only after the first. Built on **v2.3.8 "Parallax"** (2026-08-20) — **which pixels differ, not just which frame**. Parallax is the apparent shift of an object seen from two positions, and the displacement is the measurement. `Probe` could already say whether two configurations of the same ROM diverge and AT WHICH FRAME, and could say nothing about where or why: a trial reduces each frame to one `u64`, the right shape for *detecting* a difference and the wrong shape for *explaining* one — a hash says frame 412 differs and has nothing to hand to Pixel Provenance, which is where an answer actually lives. `divergence::localise` re-runs both configurations to the detected frame, keeps the full output instead of its hash, and reports the **shape** of the difference — population count, first pixel in raster order, and the inclusive bounding box — which separates kinds of bug from each other (one pixel is a sprite or a palette entry, 256 in a row is a scanline, tens of thousands is a scroll or a mode change); `is_single_scanline` is offered rather than left to call sites because the inclusive comparison is easy to get wrong. It localises on the **index** framebuffer (256x240 `u16`s of `(emphasis << 6) | colour`, the PPU's own per-pixel output before the palette lookup) — half the bytes and at least as sensitive, since the RGBA buffer is a pure function of it given the same palette. Three answers, and the third is the point: `Identical`, `Differs`, and **`Inconclusive`** for an exhausted budget or two trials that cannot be compared — the Latency Oracle precedent applies directly, "I stopped looking" must not arrive wearing the same shape as "they agree" — and the budget is checked UP FRONT for all four trials, so spending two on detection and then finding the localisation pair unaffordable cannot consume the budget that would have answered the question. Beyond locating a difference the Lens **explains** it: trial-scoped provenance capture hands a located pixel to the machinery that already answers "what wrote this, and from which instruction", and an audio lens resolves a divergence to the CPU cycle. One defect was found and fixed inside the same work — the Lens left the emulator **thirty frames ahead** of where it started, because a trial restores the anchor on the way IN and not on the way OUT (deliberate — it is what lets the Lens read the trial's final frame off `nes` directly) and the outermost caller has to put the timeline back, and did not. Cut from its own boundary commit (#407's merge) rather than from `main`, so its artifacts contain exactly the Divergence Lens. Built on **v2.3.7 "Overtone"** (2026-08-19) — the **audio-provenance** release. The APU counterpart of Pixel Provenance: a per-register write attribution answering *what wrote this, and from which instruction*, and a per-CPU-cycle mix trace answering *what were the channels actually doing* — per CPU cycle rather than per output sample, because that is the cadence at which the mix is genuinely computed, and carrying **raw** pre-mix channel values so a record describes the chip rather than the user's mixer sliders. Surfaced at **Tools → Audio → Audio Provenance**; output-only, runtime-default-off, not serialized. **Its subject is the trap it inherited.** Pixel Provenance shipped non-functional for four releases because run-ahead's per-frame rollback cleared its store after the visible frame was harvested and before the frontend released the emulator lock, so the carry landed **in the same change as the feature** here rather than after a bug report. That enumeration was then found to be incomplete: `rustynes-probe` has **three more** same-timeline restores — `Probe::run_uncounted` (once per trial, and a latency measurement runs up to **21**), `latency::measure_in_place` (the final restore, outside every per-trial guard), and the RAM Atlas panel's `TimelineGuard` — none of which used the stash, so **running the Latency Oracle or the RAM Atlas emptied both provenance panels**. Both stores are cumulative, so the records were not rebuilt by the next frame; they were gone for the session. The test named for the contract, `measure_in_place_restores_the_live_timeline`, compares `nes.snapshot()` and provenance is deliberately **not** in the snapshot — it asserted something strictly weaker than its own name and passed throughout. Closed by moving the stash into a shared `TrialGuard`, pinned by four independent mutations. **`$4014` and `$4016` were documented as attributed and were not** — the bus handles both without routing through `Apu::write_register`. **Two defects were caught by measurement rather than reading:** `apu_throughput`, built for this release, reshaped the plumbing **three times** on regressions invisible in the diff (the bench itself had to be corrected first — it omitted an end-of-cycle pair worth ~23% of true per-cycle cost), and a randomized sweep of the save-state parse boundary found **four** panics in VRC7's OPLL where hand-tracing found one, because the maximally-hostile all-`0xFF` payload set `update_requests` to all-ones and **concealed** an `eg_shift` panic. Also fixed: the **browser demo applied no per-game header corrections**, *Rad Racer*'s roadside artifact (a hybrid address spliced from a stale `v`), VRC7 save states dropping the live FM synthesizer so rewind garbled the music, and **no CI job carried a timeout** — one hung job silently skipped a release for five hours. `rustynes-apu` and `rustynes-core` both change, so **AccuracyCoin 141/141 (100.00%, RAM decoder) and nestest 0-diff are VERIFIED, not asserted.** Built on **v2.3.6 "Sounding"** (2026-08-17) — about **measuring, and what a measurement is allowed to claim**. **Two shipped features are found never to have worked.** Pixel Provenance (the v2.3.2 marquee) returned an empty report for every user on the default `run_ahead = 1`: run-ahead's per-frame rollback is the LAST thing before the frontend releases the emulator lock, so the panel's first look was always *after* the wipe — and "click any pixel" was **never implemented** (two `DragValue` spinboxes; the only `Sense` in the file was `hover()` on a colour swatch). **Two source comments and four doc claims asserted the opposite of their own code**, which is why four releases passed unchecked. And **Duck Hunt could never score**: its protocol is "see NOTHING for one frame, then a bright spot in the next", and the light bit was sampled at end-of-frame, so a read during frame N returned frame N-1 — the probe **exactly inverted** (000000 -> 000500). Two new tools, both built to **decline rather than guess**: the **Latency Oracle** (replays one moment with a button held and without it; `None` and `Some(0)` are different answers never collapsed; `START` excluded because pausing is a reaction to a *menu*; **recommends a run-ahead depth and never applies one**) and the **RAM Atlas** (classifies all 2 KiB of work RAM, then VERIFIES a candidate by perturbing it — observation returns all 2048 labels as `Untested` so it is *structurally* incapable of claiming an effect; liveness is relative to its lens and every verdict names it; `Inert` is documented as NOT meaning unused). **APU Workstream D is CLOSED** — the 18.7%-of-frame figure stands, but it is not recoverable by gating per-cycle bookkeeping: one adoption, three measured rejections, one declined on inspection, two left unmeasured deliberately. Tools and Debug are regrouped by task (Tools had reached twenty flat entries). The core gains one `const fn` getter and nothing else, so **AccuracyCoin 141/141 and nestest 0-diff are VERIFIED, not asserted**. **NOT fixed here:** `libretro/docs#1180` (the licence on the libretro docs site) is still open upstream. Built on **v2.3.5 "Manifest"** (2026-08-16) — about **what the core declares about itself**. A user reported RetroArch still showing the pre-relicense MIT/Apache-2.0 terms. It does: RetroArch reads `dist/info/rustynes_libretro.info` from **`libretro/libretro-super`**, a SEPARATE copy from this repo's that nothing syncs and nothing compared, so the v2.2.9 GPL relicense never reached it (both upstream PRs merged 2026-07-21, exactly two weeks BEFORE the 2026-08-04 relicense). The repo-side half is corrected here — `GPLv3+`, since libretro uses short tokens and marks "or later" with a trailing `+` (tallied across all 316 upstream cores) — plus a standing `libretro_info_audit.rs` that pins the local file against the workspace manifest AND the core's own `retro_get_system_info`, making the upstream sync a **copy** rather than a re-derivation. **A licence change is now a mandatory upstream-sync trigger.** Auditing the wrapper then found **five further defects, every one with correct emulation behind it**: a hardcoded 60.0988 fps for every cartridge plus `retro_get_region` unimplemented (**PAL/Dendy ran 20.2% fast**), `retro_reset` unimplemented so **RetroArch's Reset did nothing, ever** (the library default is a literal no-op), `retro_unload_game` unimplemented (Game Genie *indices* leaked across cartridges), `aspect_ratio = 0.0` (square pixels, against the desktop frontend's 8:7), and no controller info so the **Zapper was unreachable** despite `Nes::set_zapper` being fully implemented. Review caught a **use-after-free**: RetroArch shallow-`memcpy`s the outer `retro_controller_info` array but RETAINS each `types` pointer, so the description tables must be `'static` (`SET_INPUT_DESCRIPTORS` is different and safe — never generalize between environment calls). The crate went from **zero tests to eight**. Separately the APU (**18.7% of frame time**, invisible to a symbol profile because fat LTO inlines it into `cpu_clock`) gained its first throughput bench and a default-configuration mix specialization, **−3.3% to −4.2%** on `nes_run_frame_nestest`, byte-identical by construction. Declared values are now DERIVED from `rustynes_core` constants (`FRAME_DURATION_*`, `DEFAULT_SAMPLE_RATE`) rather than transcribed. Audio stays **44,100 Hz** — a matched-normalized-frequency SFDR comparison shows 44.1k and 48k are equivalent (81.6 vs 82.2 dB), so nothing is gained, and 44,100 is the only rate this project's audio is verified at. Shipped OUTPUT byte-identical, but the APU *implementation* did change (the mix specialization is a strict specialization, not a no-op), so **AccuracyCoin 141/141 and nestest 0-diff were VERIFIED, not asserted**. **NOT fixed by that release, and since RESOLVED upstream:** RetroArch showed the wrong licence until `libretro-super#2069` merged (2026-08-16 — it now reads `GPLv3+`), and RustyNES did not appear on iOS/iPadOS/tvOS until `RetroArch#19416` merged (2026-08-16, `76f60626984a` — `rustynes` is now line 268 of `pkg/apple/update-cores.sh`, between `reminiscence` and `sameboy`). Being in the build list is not the same as being installable: it arrives with the next App Store RetroArch build, on libretro's cadence. Only `libretro/docs#1180` remains open.
+**Current release: v2.4.1 "Fabric"** (2026-08-20) — the **oracle** release, opening the **v2.4.1 → v2.5.0 "Fabric"** line: a new NES core written in SystemVerilog from public hardware documentation, in a sibling repository, with this emulator as its **verification oracle**. **RustyNES is not being ported to FPGA and cannot be** — a MiSTer core is SystemVerilog compiled by Quartus 17.0.2 into a Cyclone V bitstream, and high-level synthesis of a cycle-accurate emulator's control flow does not produce usable hardware; what is buildable is a NEW implementation verified against this one. `crates/rustynes-cosim` is the boundary — a narrow C ABI a Verilator testbench links, plus a `nes_golden_export` CLI emitting five golden formats. **The provenance firewall extends to HDL** (ADR 0037): `NES_MiSTer` and `fpganes` `rtl/` are strict black boxes — instantiating one as an opaque testbench module to compare OUTPUTS is permitted, reading its source is not; anything unimplementable from documentation escalates to an ADR BEFORE any source is opened. Three design decisions are locked and each has a reason: **replay, not lockstep** (`Nes` exposes `run_frame()` and `step_instruction()` and nothing finer, and the determinism contract already makes a pre-recorded trace exactly the trace a lockstep run produces), **no DPI-C** (it puts `` `ifdef SIMULATION `` guards into RTL that must also pass Quartus — the construct that lets a simulated netlist drift from the synthesised one), and **hash first, capture on divergence** (a 4200-frame AccuracyCoin run is ~125 M cycles, ~7.5 GB as per-cycle CSV against 244 KB of 4096-cycle checkpoints). The golden framebuffer is exported **pre-palette** so a palette difference cannot masquerade as a rendering one. **v2.5.0 is scoped to "the 6502 rung closes"**, not a finished core (7–13 months FTE for a full one), and two risks are accepted in writing: `NES_MiSTer` scores 121/125 on AccuracyCoin where real Famicom AV hardware also scores ~121/125, so there is no published accuracy headroom and **the core may be declined as a duplicate**; and **the oracle can be wrong**, since 141/141 is not "matches silicon" — every rung is labelled by whether it has an INDEPENDENT oracle. **The exclusion of `rustynes-cosim` from the workspace is the load-bearing detail, and it exposed a defect in the accuracy gate itself.** The crate enables `cpu-boot-trace` and `irq-timing-trace` on `rustynes-core`, and cargo unifies features across a workspace build, so as a MEMBER it made `cargo build --workspace` compile the core ONCE with the union — measured through `--message-format=json`, not inferred. `irq-timing-trace` is not an inert branch: it selects a **different** `for sub_dot in 0..3` loop in `Bus::tick_one_cpu_cycle`, so CI's `cargo test --workspace --release --features test-roms` — the accuracy battery — was validating a scheduler no user runs, the same shape as the v2.3.4 defect where the coverage harness tested a load path no user runs. The measured cost was **+1.24% / +1.39% / +1.89%** across the three `full_frame` benches, *below* this project's own 3% adoption bar, and it never touched the shipped binary or the perf gate — published precisely because it shows performance was never the argument. Exclusion has a price (an excluded package cannot use `field.workspace = true`, and `--workspace` no longer reaches it), and both halves are closed mechanically: `cosim_manifest_audit.rs` asserts every duplicated field and lint still equals the workspace's AND that the crate is still excluded (four mutations, all caught), and CI gains explicit `fmt`, `clippy` and `test` steps — the clippy step earning its place on its first run with a `must_use_candidate` `--workspace` had never surfaced. Two more findings the crate was not looking for: **the first `run_frame()` after power-on advances ZERO cycles** (the PPU is constructed at dot 340 of the pre-render line, so the seven-cycle reset ticks past the frame wrap and leaves `frame_complete` latched — gate on `Nes::frame()`, never the call count, or a `--frames 60` loop emits a 59-frame golden under a manifest claiming 60), and **no CI invocation had ever enabled `cpu-boot-trace` or `irq-timing-trace` for clippy**, so those two core modules had never passed the lint gate (six pre-existing findings; `--workspace --all-targets` covers each crate's DEFAULT feature set only). **It also carries v2.4.0 "Concordance", which merged to `main` and was never tagged**: the seven-property atomic-write sequence v2.3.9 built for `Config::save_to` is extracted into `crate::atomic_write` and adopted everywhere — the plan named three call sites and there were FOUR, the fourth being `save_state.rs`, where a truncated write is a user's game progress, while `per_game.rs` was not in the plan at all because it LOOKS correct (it renames a sibling temp file) and held two of seven: no `fsync`, and a FIXED scratch name shared across every process. Review then found **four more places the module reported success it had not earned**, each an error discarded under a comment explaining the rest of the operation: `set_permissions` swallowed (the mode applied is the one the target ALREADY had, so a failure widens a 0600 file to the umask default), the parent-directory `fsync` swallowed together with its `File::open` (so the whole barrier could be a no-op while the module's table claimed "yes", and `EIO` passed as success), a ONE-attempt occupied-scratch retry (justified by "the counter cannot repeat a name within a process", which is true and beside the point — the collision comes from a previous process whose pid was reused), and an exhaustion cleanup that deleted a file this process had not created. Plus **a `const fn` that only failed on Windows** — `is_transient_rename_error` was `const` and called `io::Error::kind`, which is not, behind `#[cfg(windows)]`, so it compiled clean on Linux and would have turned `main` red AFTER merge; the fix moved the predicate into an always-compiled function reached through `cfg!(windows) && …`, so restoring the `const` now fails on Linux. Also v2.4.0: `Nes::timeline_generation()`, a session-local counter deliberately NOT in the save state (serializing it would make a second load of the same slot restore the same generation, so a consumer would miss it — and because it lives outside the snapshot, `snapshot_schema_audit` cannot see it); the cheat save reporting its failure in the panel instead of a `stderr` nobody reads on a windowed build; and `release_anchor_audit.rs`, pinning 15 release anchors across 10 documents, which is **described in v2.3.9's published release notes and is not in the v2.3.9 tag** — it merged in #427, after the tag was cut. `rustynes-core` changes in both halves, so **AccuracyCoin 141/141 (100.00%, RAM decoder) and nestest 0-diff are VERIFIED, not asserted.** Built on **v2.3.9 "Crucible"** (2026-08-20) — the **gates** release. A crucible tests something to destruction rather than inspecting it, and that is what this release does to the project's own checks: what they cover, what they only *appear* to cover, and where a regression could still reach `main` unchallenged. The v2.3.x line added five tools in four releases and the recurring finding across all of them was never that the emulation was wrong — it was that **a check reported a pass it had not earned**. **The docs-only CI skip had never worked**: `dorny/paths-filter`'s `predicate-quantifier` defaults to `some`, which includes a file if it matches ANY pattern, so the `code` filter's leading `'**'` matched everything and all seven `!` exclusions under it were DEAD from the day they were written — proven from a run rather than the docs (a one-file markdown PR logged `Filter code = true` / `Matching files: AGENTS.md`). Every documentation PR in the project's history had been running the full matrix, and that stopped being merely wasteful the day two docs-only PRs were *blocked* by an ARM cross-compile failure on jobs that should never have been scheduled. Fixed with **two** filter steps because the quantifier is step-level and the two filters need OPPOSITE settings: `code` needs `every`, while `accuracy` is a list of **alternatives** and becomes unsatisfiable under it — the naive one-line fix would have silently disabled the accuracy battery while repairing a different gate. Both directions are now observed on real PRs. **The accuracy battery now runs at review time** — `test-roms` was full-run-only, so a regression landed on `main` rather than on the PR that caused it; it is now also path-filtered over the chip crates, the core, `rustynes-gamedb` (it rewrites the iNES header on load, so it changes what the emulator *is* before a cycle runs), the harness and `tests/`, measured first at 11 of the last 40 merged PRs so ~72% still pay nothing. **Bounds were calibrated against a measurement rather than a claim**: the ARM provisioning step failed on three consecutive PRs with NO apt error in the log at all, and the real number was `Fetched 4201 kB in 4min 45s (14.7 kB/s)` — three orders of magnitude below normal, which made the previous ~40 MB package set *hopeless* rather than unlucky (~45 minutes; no timeout could have saved it); it was also installing a whole cross toolchain to obtain `libc6-dev-<arch>-cross`, which the comment above it had already named, because bindgen runs the **host** clang against `--sysroot` and never invokes the cross compiler. **A freeze from one cartridge kept writing into the next** — not a stale label but an active per-frame write into the wrong game, because both memory panels' freezes feed the raw-cheat overlay applied after every frame and neither was registered with the ROM-transition hook; the sweep that closed it now covers every panel under ONE rule: **derived output is discarded, user-authored input is kept, and only input that actively *writes* is neutralised** (so RAM Search baselines and reconstructed call stacks clear, while watch lists and breakpoints survive and breakpoints stay ARMED — a breakpoint halts, visible and recoverable, where a freeze writes, silent and continuous). Two negatives are recorded because they cost time to establish: the header editor LOOKS ROM-bound and is not (it is a standalone file tool), and the event panel / trace status / HD-pixel coordinates are per-frame state or preferences. **The config file is written atomically and durably** — `fs::write` truncates then writes, and saves became automatic (closing a ROM, moving a mixer slider, finishing a Latency Oracle measurement), so an interruption left the user holding a truncated `config.toml`; seven properties, and **five came from review rather than the first draft** (sibling scratch file, `fsync` before rename, parent-directory sync, `create_new(true)` for CWE-377, mode applied at creation, symlink resolution including a **broken** link, and a pid + per-call counter — the last is what makes exclusive creation adoptable at all). **Two shipped features told the truth for the first time**: movies record TWO ports (`FrameInput` models P1 and P2) while the Replay panel printed "Four Score (P1..P4)" at the moment a user decides to press Record — widening the format is a `.rnm` epoch change, so it is disclosed at three levels with the caveat printed directly under the claim it qualifies; and a failed Latency Oracle save now says so instead of being swallowed (remembering is still NOT applying — nothing touches `run_ahead`, and an inconclusive result is not remembered at all). Also: **257 lines of dead code removed** — an APU pair (34), a closed `LockstepBus` DMA-service island (183), and `drain_dma` (40), a function called on every CPU read, every CPU write and every bus cycle whose entire body was `let _ = read_addr;` and whose comments claimed the legacy service below it "stays active for the default build" — alongside **25 of 29 `#[allow(dead_code)]` attributes suppressing nothing**, established by stripping them and re-running clippy across all EIGHT gated combinations (an item can be live by default and dead on wasm, which is precisely the case that would have earned the attribute); the **SAFETY-comment rule is now a gate** (`clippy::undocumented_unsafe_blocks` — all 91 unsafe sites already carried a justification, two had it where a human reads correctly and a checker cannot, and the lint is demonstrated to fail); and two `cargo deny` advisory ignores retired on their own stated condition (their entry said to remove them once the resolve moved past quick-xml 0.40, and it had). `rustynes-apu` and `rustynes-core` both change, so **AccuracyCoin 141/141 (100.00%, RAM decoder) and nestest 0-diff are VERIFIED, not asserted** — and re-run AGAIN after the second round of deletions rather than only after the first. Built on **v2.3.8 "Parallax"** (2026-08-20) — **which pixels differ, not just which frame**. Parallax is the apparent shift of an object seen from two positions, and the displacement is the measurement. `Probe` could already say whether two configurations of the same ROM diverge and AT WHICH FRAME, and could say nothing about where or why: a trial reduces each frame to one `u64`, the right shape for *detecting* a difference and the wrong shape for *explaining* one — a hash says frame 412 differs and has nothing to hand to Pixel Provenance, which is where an answer actually lives. `divergence::localise` re-runs both configurations to the detected frame, keeps the full output instead of its hash, and reports the **shape** of the difference — population count, first pixel in raster order, and the inclusive bounding box — which separates kinds of bug from each other (one pixel is a sprite or a palette entry, 256 in a row is a scanline, tens of thousands is a scroll or a mode change); `is_single_scanline` is offered rather than left to call sites because the inclusive comparison is easy to get wrong. It localises on the **index** framebuffer (256x240 `u16`s of `(emphasis << 6) | colour`, the PPU's own per-pixel output before the palette lookup) — half the bytes and at least as sensitive, since the RGBA buffer is a pure function of it given the same palette. Three answers, and the third is the point: `Identical`, `Differs`, and **`Inconclusive`** for an exhausted budget or two trials that cannot be compared — the Latency Oracle precedent applies directly, "I stopped looking" must not arrive wearing the same shape as "they agree" — and the budget is checked UP FRONT for all four trials, so spending two on detection and then finding the localisation pair unaffordable cannot consume the budget that would have answered the question. Beyond locating a difference the Lens **explains** it: trial-scoped provenance capture hands a located pixel to the machinery that already answers "what wrote this, and from which instruction", and an audio lens resolves a divergence to the CPU cycle. One defect was found and fixed inside the same work — the Lens left the emulator **thirty frames ahead** of where it started, because a trial restores the anchor on the way IN and not on the way OUT (deliberate — it is what lets the Lens read the trial's final frame off `nes` directly) and the outermost caller has to put the timeline back, and did not. Cut from its own boundary commit (#407's merge) rather than from `main`, so its artifacts contain exactly the Divergence Lens. Built on **v2.3.7 "Overtone"** (2026-08-19) — the **audio-provenance** release. The APU counterpart of Pixel Provenance: a per-register write attribution answering *what wrote this, and from which instruction*, and a per-CPU-cycle mix trace answering *what were the channels actually doing* — per CPU cycle rather than per output sample, because that is the cadence at which the mix is genuinely computed, and carrying **raw** pre-mix channel values so a record describes the chip rather than the user's mixer sliders. Surfaced at **Tools → Audio → Audio Provenance**; output-only, runtime-default-off, not serialized. **Its subject is the trap it inherited.** Pixel Provenance shipped non-functional for four releases because run-ahead's per-frame rollback cleared its store after the visible frame was harvested and before the frontend released the emulator lock, so the carry landed **in the same change as the feature** here rather than after a bug report. That enumeration was then found to be incomplete: `rustynes-probe` has **three more** same-timeline restores — `Probe::run_uncounted` (once per trial, and a latency measurement runs up to **21**), `latency::measure_in_place` (the final restore, outside every per-trial guard), and the RAM Atlas panel's `TimelineGuard` — none of which used the stash, so **running the Latency Oracle or the RAM Atlas emptied both provenance panels**. Both stores are cumulative, so the records were not rebuilt by the next frame; they were gone for the session. The test named for the contract, `measure_in_place_restores_the_live_timeline`, compares `nes.snapshot()` and provenance is deliberately **not** in the snapshot — it asserted something strictly weaker than its own name and passed throughout. Closed by moving the stash into a shared `TrialGuard`, pinned by four independent mutations. **`$4014` and `$4016` were documented as attributed and were not** — the bus handles both without routing through `Apu::write_register`. **Two defects were caught by measurement rather than reading:** `apu_throughput`, built for this release, reshaped the plumbing **three times** on regressions invisible in the diff (the bench itself had to be corrected first — it omitted an end-of-cycle pair worth ~23% of true per-cycle cost), and a randomized sweep of the save-state parse boundary found **four** panics in VRC7's OPLL where hand-tracing found one, because the maximally-hostile all-`0xFF` payload set `update_requests` to all-ones and **concealed** an `eg_shift` panic. Also fixed: the **browser demo applied no per-game header corrections**, *Rad Racer*'s roadside artifact (a hybrid address spliced from a stale `v`), VRC7 save states dropping the live FM synthesizer so rewind garbled the music, and **no CI job carried a timeout** — one hung job silently skipped a release for five hours. `rustynes-apu` and `rustynes-core` both change, so **AccuracyCoin 141/141 (100.00%, RAM decoder) and nestest 0-diff are VERIFIED, not asserted.** Built on **v2.3.6 "Sounding"** (2026-08-17) — about **measuring, and what a measurement is allowed to claim**. **Two shipped features are found never to have worked.** Pixel Provenance (the v2.3.2 marquee) returned an empty report for every user on the default `run_ahead = 1`: run-ahead's per-frame rollback is the LAST thing before the frontend releases the emulator lock, so the panel's first look was always *after* the wipe — and "click any pixel" was **never implemented** (two `DragValue` spinboxes; the only `Sense` in the file was `hover()` on a colour swatch). **Two source comments and four doc claims asserted the opposite of their own code**, which is why four releases passed unchecked. And **Duck Hunt could never score**: its protocol is "see NOTHING for one frame, then a bright spot in the next", and the light bit was sampled at end-of-frame, so a read during frame N returned frame N-1 — the probe **exactly inverted** (000000 -> 000500). Two new tools, both built to **decline rather than guess**: the **Latency Oracle** (replays one moment with a button held and without it; `None` and `Some(0)` are different answers never collapsed; `START` excluded because pausing is a reaction to a *menu*; **recommends a run-ahead depth and never applies one**) and the **RAM Atlas** (classifies all 2 KiB of work RAM, then VERIFIES a candidate by perturbing it — observation returns all 2048 labels as `Untested` so it is *structurally* incapable of claiming an effect; liveness is relative to its lens and every verdict names it; `Inert` is documented as NOT meaning unused). **APU Workstream D is CLOSED** — the 18.7%-of-frame figure stands, but it is not recoverable by gating per-cycle bookkeeping: one adoption, three measured rejections, one declined on inspection, two left unmeasured deliberately. Tools and Debug are regrouped by task (Tools had reached twenty flat entries). The core gains one `const fn` getter and nothing else, so **AccuracyCoin 141/141 and nestest 0-diff are VERIFIED, not asserted**. **NOT fixed here:** `libretro/docs#1180` (the licence on the libretro docs site) is still open upstream. Built on **v2.3.5 "Manifest"** (2026-08-16) — about **what the core declares about itself**. A user reported RetroArch still showing the pre-relicense MIT/Apache-2.0 terms. It does: RetroArch reads `dist/info/rustynes_libretro.info` from **`libretro/libretro-super`**, a SEPARATE copy from this repo's that nothing syncs and nothing compared, so the v2.2.9 GPL relicense never reached it (both upstream PRs merged 2026-07-21, exactly two weeks BEFORE the 2026-08-04 relicense). The repo-side half is corrected here — `GPLv3+`, since libretro uses short tokens and marks "or later" with a trailing `+` (tallied across all 316 upstream cores) — plus a standing `libretro_info_audit.rs` that pins the local file against the workspace manifest AND the core's own `retro_get_system_info`, making the upstream sync a **copy** rather than a re-derivation. **A licence change is now a mandatory upstream-sync trigger.** Auditing the wrapper then found **five further defects, every one with correct emulation behind it**: a hardcoded 60.0988 fps for every cartridge plus `retro_get_region` unimplemented (**PAL/Dendy ran 20.2% fast**), `retro_reset` unimplemented so **RetroArch's Reset did nothing, ever** (the library default is a literal no-op), `retro_unload_game` unimplemented (Game Genie *indices* leaked across cartridges), `aspect_ratio = 0.0` (square pixels, against the desktop frontend's 8:7), and no controller info so the **Zapper was unreachable** despite `Nes::set_zapper` being fully implemented. Review caught a **use-after-free**: RetroArch shallow-`memcpy`s the outer `retro_controller_info` array but RETAINS each `types` pointer, so the description tables must be `'static` (`SET_INPUT_DESCRIPTORS` is different and safe — never generalize between environment calls). The crate went from **zero tests to eight**. Separately the APU (**18.7% of frame time**, invisible to a symbol profile because fat LTO inlines it into `cpu_clock`) gained its first throughput bench and a default-configuration mix specialization, **−3.3% to −4.2%** on `nes_run_frame_nestest`, byte-identical by construction. Declared values are now DERIVED from `rustynes_core` constants (`FRAME_DURATION_*`, `DEFAULT_SAMPLE_RATE`) rather than transcribed. Audio stays **44,100 Hz** — a matched-normalized-frequency SFDR comparison shows 44.1k and 48k are equivalent (81.6 vs 82.2 dB), so nothing is gained, and 44,100 is the only rate this project's audio is verified at. Shipped OUTPUT byte-identical, but the APU *implementation* did change (the mix specialization is a strict specialization, not a no-op), so **AccuracyCoin 141/141 and nestest 0-diff were VERIFIED, not asserted**. **NOT fixed by that release, and since RESOLVED upstream:** RetroArch showed the wrong licence until `libretro-super#2069` merged (2026-08-16 — it now reads `GPLv3+`), and RustyNES did not appear on iOS/iPadOS/tvOS until `RetroArch#19416` merged (2026-08-16, `76f60626984a` — `rustynes` is now line 268 of `pkg/apple/update-cores.sh`, between `reminiscence` and `sameboy`). Being in the build list is not the same as being installable: it arrives with the next App Store RetroArch build, on libretro's cadence. Only `libretro/docs#1180` remains open.
 
 The prior release, **v2.3.4 "Ledger"** (2026-08-15), was the **coverage** release. Three boards land: **mapper 176 submapper 2** (WAIXING-FS005 — the `$A001` RAM Configuration Register with 32 KiB banked WRAM, the `$5000-$5FFF` register-window disable the Waixing copy-protection is built on, a mapper-195-like mixed CHR-ROM/CHR-RAM mode, two-bit `$A000` mirroring, the `$46`/`$47` bank-select swap that does NOT apply to `$06`/`$07`, PRG A21-A25, and the board's documented `$E003` decode mask), **154** (NAMCOT-3453 — mapper 88 plus a one-screen nametable bit decoded across the WHOLE `$8000-$FFFF` range, not just the bank-select window) and **243** (Sachen SA-020A — mapper 150's ASIC on its own PCB, same three registers at INVERTED significance, which is why they need separate numbers). Breadth **172 → 174 families** (51 Core + 95 Curated + 28 BestEffort). All three implemented from the NESdev wiki with **no reference-emulator source consulted**, unlike the FK23C transforms beside them which stay a disclosed Mesen2 derivation.
 
@@ -203,7 +203,7 @@ These cross-cutting decisions span multiple files. Reading individual chip docs
 - `ref-docs/` is immutable. Research updates go in dated supplemental files.
 - ADRs go in `docs/adr/` (Michael Nygard format).
 - `rustynes-core` re-exports the public types from the chip crates; downstream consumers (`rustynes-frontend`, `rustynes-test-harness`) should depend on `rustynes-core` rather than the chip crates directly.
-- When relabeling old engine "v2.x" narrative for users, present it as upstream lineage/history — **never as a current RustyNES release version.** The current release is **v2.3.9 "Crucible"** (2026-08-20, the gates release — a crucible tests to destruction rather than inspects, and this one does that to the project's own checks. The docs-only CI skip HAD NEVER WORKED [`predicate-quantifier` defaults to `some`, so the `code` filter's `'**'` matched everything and all seven `!` exclusions were dead from the day they were written]; fixed with TWO filter steps because the quantifier is step-level and `accuracy` is a list of alternatives that becomes unsatisfiable under `every` — the one-line fix would have silently disabled the accuracy battery. `test-roms` now runs at review time, path-filtered over the chip crates, the core, `rustynes-gamedb`, the harness and `tests/` [11 of the last 40 merged PRs]. A freeze from one cartridge kept writing into the next — an active per-frame write into the wrong game — closed by a ROM-transition sweep under one rule: derived output discarded, user-authored input kept, and only input that actively WRITES neutralised. The config file is written atomically and durably [seven properties, five from review]. Movies record two ports while the Replay panel advertised "Four Score (P1..P4)", now disclosed at three levels. 257 lines of dead code removed, 25 of 29 `#[allow(dead_code)]` attributes suppressing nothing, `undocumented_unsafe_blocks` made a gate, and two `cargo deny` ignores retired on their own stated condition. `rustynes-apu` and `rustynes-core` both change, so AccuracyCoin 141/141 and nestest 0-diff are VERIFIED), on top of **v2.3.8 "Parallax"** (2026-08-20, the Divergence Lens — `Probe` could say two configurations diverge and AT WHICH FRAME and nothing about where or why, because a trial reduces each frame to one `u64`; `divergence::localise` keeps the full output and reports the SHAPE of the difference [population count, first pixel in raster order, inclusive bounding box], localises on the INDEX framebuffer so a palette difference cannot masquerade as a rendering one, hands the located pixel to Pixel Provenance, and answers `Inconclusive` rather than collapsing "I stopped looking" into "they agree". Cut from its own boundary commit, so its artifacts contain exactly the Lens), on top of **v2.3.7 "Overtone"** (2026-08-19, the audio-provenance release — the APU counterpart of Pixel Provenance: a per-register write attribution [*what wrote this, and from which instruction*] plus a per-CPU-cycle mix trace [*what were the channels actually doing*], at Tools → Audio → Audio Provenance, output-only and runtime-default-off. Its real subject is the trap it inherited: Pixel Provenance shipped non-functional for four releases because run-ahead's rollback cleared its store before any UI could read it, so the carry landed in the SAME change as the feature — and then the same defect turned up in THREE more places, every restore in `rustynes-probe`, so running the Latency Oracle or the RAM Atlas silently emptied both provenance panels [the v2.3.6 fix had enumerated one caller rather than the mechanism, and `measure_in_place_restores_the_live_timeline` could not see the breach because provenance is deliberately not in the snapshot]. Two defects found by measurement not reading: the new `apu_throughput` bench reshaped the plumbing three times on regressions invisible in the diff, and a randomized sweep of the save-state parse boundary found FOUR panics in VRC7's OPLL where hand-tracing found one — the all-`0xFF` payload CONCEALED one. Also fixed: `$4014`/`$4016` documented as attributed and were not, the browser demo applied no per-game header corrections, Rad Racer's roadside artifact, VRC7 save states dropping the live FM synthesizer, and unbounded CI jobs. `rustynes-apu` and `rustynes-core` both change, so AccuracyCoin 141/141 and nestest 0-diff are VERIFIED), on top of **v2.3.6 "Sounding"** (2026-08-17, the measurement release — two shipped features found never to have worked [Pixel Provenance's record wiped by run-ahead before any UI could read it, its click never implemented; the Duck Hunt Zapper probe exactly inverted], the Latency Oracle and RAM Atlas both built to decline rather than guess, APU Workstream D closed on three measured rejections, and the Tools/Debug menus regrouped by task; core gains one `const fn` getter so AccuracyCoin 141/141 is VERIFIED), on top of **v2.3.5 "Manifest"** (2026-08-16, the declaration release — the libretro `.info` RetroArch reads is a SEPARATE upstream copy the GPL relicense never reached, corrected to `GPLv3+` with a standing audit; five wrapper defects each with correct emulation behind them [PAL 20.2% fast, Reset inert, unload leaked cheat indices, square-pixel aspect, Zapper unreachable]; a use-after-free in the controller tables found in review; the APU's first throughput bench + a −3.3%/−4.2% default-mix specialization; AccuracyCoin 141/141 VERIFIED. The RetroArch licence display and iOS/iPadOS/tvOS availability both remain blocked on upstream PRs), on top of **v2.3.4 "Ledger"** (2026-08-15, the coverage release — mappers 176/2 (WAIXING-FS005), 154 (NAMCOT-3453) and 243 (Sachen SA-020A) taking breadth to 174 families; the coverage harness moved onto the frontend's real load path, exposing a per-game-database defect that had made every Sachen cartridge unloadable since v1.2.0; this one TOUCHES the core, so AccuracyCoin 141/141 is verified, not by construction; Workstream C — the APU at 18.7% — was NOT delivered and is carried to v2.3.5), on top of **v2.3.3 "Cadence"** (2026-08-14, the display-pacing release — the run-ahead throttle oscillation traced to a stale median, a predictive engage arm, and the `wp_presentation` apparatus; frontend-only, AccuracyCoin 141/141), on top of **v2.3.2 "Lucid"** (2026-08-11, the pixel-provenance release — per-byte write attribution + the per-pixel causal record + the Tools → Pixel Provenance panel + deterministic replay attestation via `rustynes verify`; all `debug-hooks`-gated and output-only, so AccuracyCoin holds 141/141 and nestest is 0-diff), on top of **v2.3.1 "Plumb Line"** (2026-08-06, the measurement release — ten hot-path candidates measured and all ten rejected), itself on **v2.3.0 "Datum II"** (2026-08-05, the capstone closing the v2.2.6 → v2.3.0 NESdev-remediation line — **true multi-viewport OS-window detach** for every tool panel (v2.2.9's affordance only *embedded* them, so the Windows-10 trapped-window report is now genuinely fixed); a **frame-pacing fix** predating that work (the render path held the emulator lock across the blocking swapchain acquire + present, stalling frame production whenever a debugger panel was open — now split so the lock covers only the egui UI build, plus `pace_frames` reading a lock-free `has_rom` atomic instead of locking every `about_to_wait`); a **−5.13% / −3.51%** byte-identical PPU optimization (`v2.3.0 P1`: `#[inline]` on the per-dot sprite eval + hoisting the `tick_oam_bus` early-out); both remaining forum-reported accuracy items (SMB left edge, Rad Racer hybrid-address) **verified already-correct**; and the AccuracyCoin gate pinned to an **exact 141/141**), on top of **v2.2.9 "Studio II"** (2026-08-04, a frontend quality-of-life release — TAStudio piano-roll edits wired to the emulator, `.bk2` playback honoring the movie's `LogKey` column order, and a detach/pop-out affordance for tool windows (the shared `detachable_window` helper across 18 panels) [native-only; it **embedded** the panel on the single-viewport `egui_winit` integration rather than opening a separate OS window — **resolved in v2.3.0** by the real multi-viewport implementation]; frontend-only so the deterministic core is untouched and AccuracyCoin holds 141/141, nestest 0-diff), on top of **v2.2.8 "Aperture II"** (2026-08-04, a presentation-fidelity release — gamma-correct scanlines + a WebGL2 gamma fix + a sharper scanline profile; presentation-only so the pre-shader framebuffer + AccuracyCoin 141/141 are byte-identical, native default unchanged; visual verification pending), on top of **v2.2.7 "Timbre II"** (2026-08-04, an expansion-audio fidelity release — VRC6 recalibrated to ~1.0× a 2A03 pulse per the NESdev/field consensus [`VRC6_MIX_SCALE` 979→650; Mesen2's ~1.5× was the loud outlier], and the Sunsoft 5B envelope moved to the exact 5-bit 1.5 dB/step DAC; expansion-only, so the base 2A03 is byte-identical and AccuracyCoin holds 141/141), on top of **v2.2.6 "Almanac"** (2026-08-04, a de-monetization + provenance release — RustyNES is permanently open-source and income-free per ADR 0035; all planned monetization removed, native apps kept as free FOSS apps, and the TriCNES hybrid-address timing-calibration caveat disclosed per ADR 0030 for a v2.3.0 rework; zero emulation-core behavior changes so AccuracyCoin holds 141/141 by construction), on top of **v2.2.5 "Colophon"** (2026-08-03, a provenance/licensing/documentation-integrity release — zero emulation-core behavior changes so AccuracyCoin holds 141/141 by construction; `NOTICE` rewritten for full attribution + GPL-oracle disclosure + GeraNES, in-source "port" comments reworded to the oracle framing, the CRT-shader/NTSC provenance reworded to independent reimplementations, `docs/originality-and-provenance.md` added, README AI-assistance disclosure), on top of **v2.2.4 "Cartridge"** (2026-07-24, a libretro/RetroArch distribution cut — zero emulation-core changes so AccuracyCoin holds 141/141 by construction; the libretro core is confirmed up-to-date with all recent changes and builds for the buildbot ABIs [`x86_64-pc-windows-gnu`, `aarch64-linux-android`], and `rustynes_libretro.info` is corrected: `disk_control` false→true [the FDS Disk Control interface was wired but advertised absent], `display_version` v1.0.0→v2.2.4, mapper count 168→172; core options remain a documented future enhancement; the Antigravity reviewer standardization rides along), on top of **v2.2.3 "Datum"** (2026-07-23, a performance and accuracy-closure patch — the fast PPU dot path promoted to default and exposed, PGO binaries shipped on the release path, a same-runner relative frame-time CI gate, the last two Holy Mapperel residuals closed [MMC1 WRAM write-protect + FME-7 open bus, all 17 ROMs now `detail=0000`], the Sunsoft 5B level calibrated with `Mapper::mix_audio` widened to i32, a save-state schema gap fixed at `PPU_SNAPSHOT_VERSION` 8 + an APU v4 tail, an opt-in Zapper beam-relative light model, and the eleven `sprintN.rs` mapper modules renamed to `mNNN_<board>.rs`; two optimizations measured and REJECTED and documented as such; AccuracyCoin 141/141 — on top of **v2.2.2 "Conduit"** [2026-07-21, a build/distribution/CI-integrity patch — the libretro buildbot recipe taken from 1 of 10 jobs green to all ten building, a GitHub Actions supply-chain hardening pass, and the toolchain collapsed to one pinned source of truth with no `nightly` on any build path; zero emulation-core changes], itself on **v2.2.1** [2026-07-15, a housekeeping patch: dev-tooling archival, a zero-source-change dependency consolidation, and a gitignored FDS test-corpus addition], itself on **v2.2.0 "Capstone"** [2026-07-12], the milestone cut that closes the v2.1.5 → v2.2.0 "deepen the existing project" run — its two remaining marquees the netplay matchmaking / lobby stack and the FDS medium model, atop a peripherals + quality/security pass (Famicom `$4016`-bit-2 microphone + 3×3-aperture Zapper; cargo-fuzz targets 3 → 8 finding + fixing two `Movie::deserialize` OOM-DoS paths; a read-only Tools → ROM Info browser); every change additive or default-off, AccuracyCoin 141/141) on the v2.0.0 "Timebase" one-clock / every-cycle-bus-access scheduler rewrite + Vs. `DualSystem` dual-console support. The v2.0.x "Harbor" mobile-finalization train (v2.0.1→v2.0.9) and the entire v2.1.x "Fathom" line (v2.1.0→v2.1.10) plus the v2.2.0 "Capstone" milestone have all shipped — the run's steps being v2.1.5 "Vernier" (regression-net & residual) → v2.1.6 "Timbre" (expansion-audio fidelity) → v2.1.7 "Stepping" (opt-in PPU/2A03 die-revisions + power-on RAM/palette models; the DMA "unexpected read" frontier a documented no-op on every oracle, ADR 0033) → v2.1.8 "Tempo" (a default-OFF fast PPU dot path + SIMD blitter + wasm size pass) → v2.1.9 "Aperture" (a marquee CRT shader stack + raw NTSC composite signal-decode + GIF/WAV capture + palette editor) → v2.1.10 "Loom" (TAStudio greenzone + Lua API breadth + browser-RA auth-proxy deploy stack + Vs. `DualSystem` libretro presentation) → v2.2.0 "Capstone" (the milestone cut closing the run) → v2.2.1 (housekeeping) → **v2.2.2 "Conduit"** the build/distribution/CI-integrity patch — preceded by v1.10.0 "Arcade" the native Libretro / RetroArch core, the v1.9.0→v1.9.9 iOS TestFlight train, the v1.8.0→v1.8.9 "Android" train, and the desktop-feature lineage v1.1.0→v1.7.1, all on the v1.0.0 production core (see the top "Current release" block + `docs/STATUS.md`). **Never claim any version *later* than v2.3.9 is released** — the **v2.2.6 → v2.3.0** line (de-monetization + NESdev remediation: audio [v2.2.7, shipped], video/gamma [v2.2.8, shipped], TAS/UX [v2.2.9, shipped], and the PPU left-edge + hybrid-address accuracy capstone at **v2.3.0** "Datum II" [shipped]) is now **complete**. The freed **v2.3.0** slot is repurposed as that accuracy capstone (NOT a store launch — RustyNES is now income-free per ADR 0035; any free mobile-app store listing is a later, unversioned step with no monetization — see `to-dos/ROADMAP.md`). Two distinct "v2.0"s exist and must not be conflated, **both now shipped, at different times, for different reasons**: the **engine-lineage v2.0** master-clock work shipped as the **v1.0.0** production core (2026-06-13) — it was the *only* scheduler through v1.10.0. RustyNES's own **v2.0.0 "Timebase"** release (2026-07-03) is a *different* milestone that *replaces* that same dot-lockstep scheduler outright: the **one-clock + every-cycle-bus-access collapse** (a single canonical cycle counter + a split-around-the-access `start_cycle`/`end_cycle` PPU catch-up, mirroring Mesen2's structure), full Vs. `DualSystem` dual-console emulation (core-and-harness-only; frontend wiring deferred), and the breaking save-state / cross-version changes it entailed (ADR 0002 / ADR 0028 / ADR 0029) — the one release that broke byte-identity / save-state compatibility, by design. The R1/R2 hard-tier MMC3 IRQ-timing residual was investigated under a bounded-effort campaign and is by-design-deferred beyond v2.0.0, not closed — see ADR 0002's decision-update section for the mechanism-level finding.
+- When relabeling old engine "v2.x" narrative for users, present it as upstream lineage/history — **never as a current RustyNES release version.** The current release is **v2.4.1 "Fabric"** (2026-08-20, the oracle release opening the v2.4.1 → v2.5.0 "Fabric" line — a new NES core in SystemVerilog written from public hardware documentation in a sibling repository, with RustyNES as its VERIFICATION ORACLE; RustyNES is not being ported to FPGA and cannot be. `crates/rustynes-cosim` is the boundary (a narrow C ABI a Verilator testbench links, plus `nes_golden_export`), the firewall extends to HDL per ADR 0037 (`NES_MiSTer` and `fpganes` `rtl/` are strict black boxes), and v2.5.0 is scoped to "the 6502 rung closes" rather than a finished core. Excluding the crate from the workspace is the load-bearing detail: cargo unifies features, `irq-timing-trace` selects a DIFFERENT per-dot loop in `Bus::tick_one_cpu_cycle`, and the accuracy battery was therefore validating a scheduler no user runs. Also found: the first `run_frame()` after power-on advances ZERO cycles, and two trace-gated core modules had never been linted. It CARRIES v2.4.0 "Concordance", which merged to `main` and was never tagged — atomic durable writes on every path that persists user data (four call sites, four further silent successes found in review), `Nes::timeline_generation()`, and the 15-anchor release audit. AccuracyCoin 141/141 and nestest 0-diff VERIFIED), on top of **v2.3.9 "Crucible"** (2026-08-20, the gates release — a crucible tests to destruction rather than inspects, and this one does that to the project's own checks. The docs-only CI skip HAD NEVER WORKED [`predicate-quantifier` defaults to `some`, so the `code` filter's `'**'` matched everything and all seven `!` exclusions were dead from the day they were written]; fixed with TWO filter steps because the quantifier is step-level and `accuracy` is a list of alternatives that becomes unsatisfiable under `every` — the one-line fix would have silently disabled the accuracy battery. `test-roms` now runs at review time, path-filtered over the chip crates, the core, `rustynes-gamedb`, the harness and `tests/` [11 of the last 40 merged PRs]. A freeze from one cartridge kept writing into the next — an active per-frame write into the wrong game — closed by a ROM-transition sweep under one rule: derived output discarded, user-authored input kept, and only input that actively WRITES neutralised. The config file is written atomically and durably [seven properties, five from review]. Movies record two ports while the Replay panel advertised "Four Score (P1..P4)", now disclosed at three levels. 257 lines of dead code removed, 25 of 29 `#[allow(dead_code)]` attributes suppressing nothing, `undocumented_unsafe_blocks` made a gate, and two `cargo deny` ignores retired on their own stated condition. `rustynes-apu` and `rustynes-core` both change, so AccuracyCoin 141/141 and nestest 0-diff are VERIFIED), on top of **v2.3.8 "Parallax"** (2026-08-20, the Divergence Lens — `Probe` could say two configurations diverge and AT WHICH FRAME and nothing about where or why, because a trial reduces each frame to one `u64`; `divergence::localise` keeps the full output and reports the SHAPE of the difference [population count, first pixel in raster order, inclusive bounding box], localises on the INDEX framebuffer so a palette difference cannot masquerade as a rendering one, hands the located pixel to Pixel Provenance, and answers `Inconclusive` rather than collapsing "I stopped looking" into "they agree". Cut from its own boundary commit, so its artifacts contain exactly the Lens), on top of **v2.3.7 "Overtone"** (2026-08-19, the audio-provenance release — the APU counterpart of Pixel Provenance: a per-register write attribution [*what wrote this, and from which instruction*] plus a per-CPU-cycle mix trace [*what were the channels actually doing*], at Tools → Audio → Audio Provenance, output-only and runtime-default-off. Its real subject is the trap it inherited: Pixel Provenance shipped non-functional for four releases because run-ahead's rollback cleared its store before any UI could read it, so the carry landed in the SAME change as the feature — and then the same defect turned up in THREE more places, every restore in `rustynes-probe`, so running the Latency Oracle or the RAM Atlas silently emptied both provenance panels [the v2.3.6 fix had enumerated one caller rather than the mechanism, and `measure_in_place_restores_the_live_timeline` could not see the breach because provenance is deliberately not in the snapshot]. Two defects found by measurement not reading: the new `apu_throughput` bench reshaped the plumbing three times on regressions invisible in the diff, and a randomized sweep of the save-state parse boundary found FOUR panics in VRC7's OPLL where hand-tracing found one — the all-`0xFF` payload CONCEALED one. Also fixed: `$4014`/`$4016` documented as attributed and were not, the browser demo applied no per-game header corrections, Rad Racer's roadside artifact, VRC7 save states dropping the live FM synthesizer, and unbounded CI jobs. `rustynes-apu` and `rustynes-core` both change, so AccuracyCoin 141/141 and nestest 0-diff are VERIFIED), on top of **v2.3.6 "Sounding"** (2026-08-17, the measurement release — two shipped features found never to have worked [Pixel Provenance's record wiped by run-ahead before any UI could read it, its click never implemented; the Duck Hunt Zapper probe exactly inverted], the Latency Oracle and RAM Atlas both built to decline rather than guess, APU Workstream D closed on three measured rejections, and the Tools/Debug menus regrouped by task; core gains one `const fn` getter so AccuracyCoin 141/141 is VERIFIED), on top of **v2.3.5 "Manifest"** (2026-08-16, the declaration release — the libretro `.info` RetroArch reads is a SEPARATE upstream copy the GPL relicense never reached, corrected to `GPLv3+` with a standing audit; five wrapper defects each with correct emulation behind them [PAL 20.2% fast, Reset inert, unload leaked cheat indices, square-pixel aspect, Zapper unreachable]; a use-after-free in the controller tables found in review; the APU's first throughput bench + a −3.3%/−4.2% default-mix specialization; AccuracyCoin 141/141 VERIFIED. The RetroArch licence display and iOS/iPadOS/tvOS availability both remain blocked on upstream PRs), on top of **v2.3.4 "Ledger"** (2026-08-15, the coverage release — mappers 176/2 (WAIXING-FS005), 154 (NAMCOT-3453) and 243 (Sachen SA-020A) taking breadth to 174 families; the coverage harness moved onto the frontend's real load path, exposing a per-game-database defect that had made every Sachen cartridge unloadable since v1.2.0; this one TOUCHES the core, so AccuracyCoin 141/141 is verified, not by construction; Workstream C — the APU at 18.7% — was NOT delivered and is carried to v2.3.5), on top of **v2.3.3 "Cadence"** (2026-08-14, the display-pacing release — the run-ahead throttle oscillation traced to a stale median, a predictive engage arm, and the `wp_presentation` apparatus; frontend-only, AccuracyCoin 141/141), on top of **v2.3.2 "Lucid"** (2026-08-11, the pixel-provenance release — per-byte write attribution + the per-pixel causal record + the Tools → Pixel Provenance panel + deterministic replay attestation via `rustynes verify`; all `debug-hooks`-gated and output-only, so AccuracyCoin holds 141/141 and nestest is 0-diff), on top of **v2.3.1 "Plumb Line"** (2026-08-06, the measurement release — ten hot-path candidates measured and all ten rejected), itself on **v2.3.0 "Datum II"** (2026-08-05, the capstone closing the v2.2.6 → v2.3.0 NESdev-remediation line — **true multi-viewport OS-window detach** for every tool panel (v2.2.9's affordance only *embedded* them, so the Windows-10 trapped-window report is now genuinely fixed); a **frame-pacing fix** predating that work (the render path held the emulator lock across the blocking swapchain acquire + present, stalling frame production whenever a debugger panel was open — now split so the lock covers only the egui UI build, plus `pace_frames` reading a lock-free `has_rom` atomic instead of locking every `about_to_wait`); a **−5.13% / −3.51%** byte-identical PPU optimization (`v2.3.0 P1`: `#[inline]` on the per-dot sprite eval + hoisting the `tick_oam_bus` early-out); both remaining forum-reported accuracy items (SMB left edge, Rad Racer hybrid-address) **verified already-correct**; and the AccuracyCoin gate pinned to an **exact 141/141**), on top of **v2.2.9 "Studio II"** (2026-08-04, a frontend quality-of-life release — TAStudio piano-roll edits wired to the emulator, `.bk2` playback honoring the movie's `LogKey` column order, and a detach/pop-out affordance for tool windows (the shared `detachable_window` helper across 18 panels) [native-only; it **embedded** the panel on the single-viewport `egui_winit` integration rather than opening a separate OS window — **resolved in v2.3.0** by the real multi-viewport implementation]; frontend-only so the deterministic core is untouched and AccuracyCoin holds 141/141, nestest 0-diff), on top of **v2.2.8 "Aperture II"** (2026-08-04, a presentation-fidelity release — gamma-correct scanlines + a WebGL2 gamma fix + a sharper scanline profile; presentation-only so the pre-shader framebuffer + AccuracyCoin 141/141 are byte-identical, native default unchanged; visual verification pending), on top of **v2.2.7 "Timbre II"** (2026-08-04, an expansion-audio fidelity release — VRC6 recalibrated to ~1.0× a 2A03 pulse per the NESdev/field consensus [`VRC6_MIX_SCALE` 979→650; Mesen2's ~1.5× was the loud outlier], and the Sunsoft 5B envelope moved to the exact 5-bit 1.5 dB/step DAC; expansion-only, so the base 2A03 is byte-identical and AccuracyCoin holds 141/141), on top of **v2.2.6 "Almanac"** (2026-08-04, a de-monetization + provenance release — RustyNES is permanently open-source and income-free per ADR 0035; all planned monetization removed, native apps kept as free FOSS apps, and the TriCNES hybrid-address timing-calibration caveat disclosed per ADR 0030 for a v2.3.0 rework; zero emulation-core behavior changes so AccuracyCoin holds 141/141 by construction), on top of **v2.2.5 "Colophon"** (2026-08-03, a provenance/licensing/documentation-integrity release — zero emulation-core behavior changes so AccuracyCoin holds 141/141 by construction; `NOTICE` rewritten for full attribution + GPL-oracle disclosure + GeraNES, in-source "port" comments reworded to the oracle framing, the CRT-shader/NTSC provenance reworded to independent reimplementations, `docs/originality-and-provenance.md` added, README AI-assistance disclosure), on top of **v2.2.4 "Cartridge"** (2026-07-24, a libretro/RetroArch distribution cut — zero emulation-core changes so AccuracyCoin holds 141/141 by construction; the libretro core is confirmed up-to-date with all recent changes and builds for the buildbot ABIs [`x86_64-pc-windows-gnu`, `aarch64-linux-android`], and `rustynes_libretro.info` is corrected: `disk_control` false→true [the FDS Disk Control interface was wired but advertised absent], `display_version` v1.0.0→v2.2.4, mapper count 168→172; core options remain a documented future enhancement; the Antigravity reviewer standardization rides along), on top of **v2.2.3 "Datum"** (2026-07-23, a performance and accuracy-closure patch — the fast PPU dot path promoted to default and exposed, PGO binaries shipped on the release path, a same-runner relative frame-time CI gate, the last two Holy Mapperel residuals closed [MMC1 WRAM write-protect + FME-7 open bus, all 17 ROMs now `detail=0000`], the Sunsoft 5B level calibrated with `Mapper::mix_audio` widened to i32, a save-state schema gap fixed at `PPU_SNAPSHOT_VERSION` 8 + an APU v4 tail, an opt-in Zapper beam-relative light model, and the eleven `sprintN.rs` mapper modules renamed to `mNNN_<board>.rs`; two optimizations measured and REJECTED and documented as such; AccuracyCoin 141/141 — on top of **v2.2.2 "Conduit"** [2026-07-21, a build/distribution/CI-integrity patch — the libretro buildbot recipe taken from 1 of 10 jobs green to all ten building, a GitHub Actions supply-chain hardening pass, and the toolchain collapsed to one pinned source of truth with no `nightly` on any build path; zero emulation-core changes], itself on **v2.2.1** [2026-07-15, a housekeeping patch: dev-tooling archival, a zero-source-change dependency consolidation, and a gitignored FDS test-corpus addition], itself on **v2.2.0 "Capstone"** [2026-07-12], the milestone cut that closes the v2.1.5 → v2.2.0 "deepen the existing project" run — its two remaining marquees the netplay matchmaking / lobby stack and the FDS medium model, atop a peripherals + quality/security pass (Famicom `$4016`-bit-2 microphone + 3×3-aperture Zapper; cargo-fuzz targets 3 → 8 finding + fixing two `Movie::deserialize` OOM-DoS paths; a read-only Tools → ROM Info browser); every change additive or default-off, AccuracyCoin 141/141) on the v2.0.0 "Timebase" one-clock / every-cycle-bus-access scheduler rewrite + Vs. `DualSystem` dual-console support. The v2.0.x "Harbor" mobile-finalization train (v2.0.1→v2.0.9) and the entire v2.1.x "Fathom" line (v2.1.0→v2.1.10) plus the v2.2.0 "Capstone" milestone have all shipped — the run's steps being v2.1.5 "Vernier" (regression-net & residual) → v2.1.6 "Timbre" (expansion-audio fidelity) → v2.1.7 "Stepping" (opt-in PPU/2A03 die-revisions + power-on RAM/palette models; the DMA "unexpected read" frontier a documented no-op on every oracle, ADR 0033) → v2.1.8 "Tempo" (a default-OFF fast PPU dot path + SIMD blitter + wasm size pass) → v2.1.9 "Aperture" (a marquee CRT shader stack + raw NTSC composite signal-decode + GIF/WAV capture + palette editor) → v2.1.10 "Loom" (TAStudio greenzone + Lua API breadth + browser-RA auth-proxy deploy stack + Vs. `DualSystem` libretro presentation) → v2.2.0 "Capstone" (the milestone cut closing the run) → v2.2.1 (housekeeping) → **v2.2.2 "Conduit"** the build/distribution/CI-integrity patch — preceded by v1.10.0 "Arcade" the native Libretro / RetroArch core, the v1.9.0→v1.9.9 iOS TestFlight train, the v1.8.0→v1.8.9 "Android" train, and the desktop-feature lineage v1.1.0→v1.7.1, all on the v1.0.0 production core (see the top "Current release" block + `docs/STATUS.md`). **Never claim any version *later* than v2.4.1 is released** — the **v2.2.6 → v2.3.0** line (de-monetization + NESdev remediation: audio [v2.2.7, shipped], video/gamma [v2.2.8, shipped], TAS/UX [v2.2.9, shipped], and the PPU left-edge + hybrid-address accuracy capstone at **v2.3.0** "Datum II" [shipped]) is now **complete**. The freed **v2.3.0** slot is repurposed as that accuracy capstone (NOT a store launch — RustyNES is now income-free per ADR 0035; any free mobile-app store listing is a later, unversioned step with no monetization — see `to-dos/ROADMAP.md`). Two distinct "v2.0"s exist and must not be conflated, **both now shipped, at different times, for different reasons**: the **engine-lineage v2.0** master-clock work shipped as the **v1.0.0** production core (2026-06-13) — it was the *only* scheduler through v1.10.0. RustyNES's own **v2.0.0 "Timebase"** release (2026-07-03) is a *different* milestone that *replaces* that same dot-lockstep scheduler outright: the **one-clock + every-cycle-bus-access collapse** (a single canonical cycle counter + a split-around-the-access `start_cycle`/`end_cycle` PPU catch-up, mirroring Mesen2's structure), full Vs. `DualSystem` dual-console emulation (core-and-harness-only; frontend wiring deferred), and the breaking save-state / cross-version changes it entailed (ADR 0002 / ADR 0028 / ADR 0029) — the one release that broke byte-identity / save-state compatibility, by design. The R1/R2 hard-tier MMC3 IRQ-timing residual was investigated under a bounded-effort campaign and is by-design-deferred beyond v2.0.0, not closed — see ADR 0002's decision-update section for the mechanism-level finding.
 - **Forward plans + roadmap live in `to-dos/`.** `to-dos/ROADMAP.md` (updated in #129) is the planning entry point and frames the release line + "the path to v2.0.0 and beyond"; `to-dos/plans/` holds the per-release plan docs (through `v1.7.0-forge-plan.md` on `main`, plus the staged-forward `v1.8.0-android-plan.md` / `v1.9.0-ios-plan.md` / `v2.0.0-master-clock-plan.md`) + the `to-dos/plans/engine-lineage/` history archive + a `to-dos/plans/research/` reference-mining archive.
 - The v1.0.0 release + GitHub Pages/CI + post-release record is in `docs/v1.0.0-synthesis-handoff-2026-06-13.md` — read it before touching CI, Pages, or release tooling. Full per-release history is in `CHANGELOG.md`.
 - **Markdownlint is a CI gate** (pre-commit, pinned `markdownlint-cli v0.39.0`). The local `markdownlint` binary is a newer version that reports rules v0.39.0 lacks (e.g. MD060) — those are NOT gated; verify with `pre-commit run markdownlint --all-files`, not the bare binary. `.markdownlint.json` keeps `MD013`/`MD033`/`MD041` disabled by design (long technical tables, the README HTML banner/`<img>`, the HTML-led README). `.markdownlintignore` exempts `ref-docs/`, `ref-proj/` (the reference-emulator clone, now removed from disk but kept in the ignore lists as a firewall guard so it can never re-enter the tree — see the MOST IMPORTANT RULE section above), the vendored `tricnes/` + upstream READMEs, and the frozen `docs/archive/` + `to-dos/archive/` trees — don't lint or reformat those.
diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index 21861e61..78346ce0 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -2,7 +2,7 @@
 
 **Document Version:** 2.1.0
 **Last Updated:** 2026-08-20
-**Applies to:** RustyNES v2.3.9 (the scheduling model is v2.0.0 "Timebase" onward)
+**Applies to:** RustyNES v2.4.1 (the scheduling model is v2.0.0 "Timebase" onward)
 
 This document fixes the high-level architecture of RustyNES. The per-subsystem specs under `docs/` (`cpu-6502.md`, `ppu-2c02.md`, `apu-2a03.md`, `mappers.md`, `scheduler.md`) take these decisions as given and elaborate one chip each. After reading this you should know the workspace shape, the scheduling model, the public boundary, and the load-bearing invariants. The canonical, always-current architecture spec is [`docs/architecture.md`](docs/architecture.md); this file is the top-level companion.
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f885b830..f5ca4384 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,13 @@ cycle-accurate core later replaced.
 
 ## [Unreleased]
 
+## [2.4.1] - 2026-08-20 - "Fabric" (RustyNES as the oracle a new implementation is verified against)
+
+This release also carries **v2.4.0 "Concordance"**, which merged to `main` and was never
+tagged; entries below marked *(v2.4.0 item)* belong to it. Two further entries — the
+standing release-anchor audit and the deferred-backlog sweep — belong to neither, having
+landed between the two, and are called out where they appear.
+
 ### Added
 
 - **`rustynes-cosim` — RustyNES as a co-simulation oracle for an FPGA
@@ -221,7 +228,7 @@ cycle-accurate core later replaced.
   that diagnostic.
 
 - **A standing release-anchor audit — the drift v2.3.9 corrected by hand cannot
-  recur silently.** `crates/rustynes-test-harness/tests/release_anchor_audit.rs`
+  recur silently.** (Landed between v2.4.0 and v2.4.1; part of neither.) `crates/rustynes-test-harness/tests/release_anchor_audit.rs`
   pins **15 anchors across 10 documents** against `[workspace.package] version`:
   the README badge and Current Release section, `docs/STATUS.md`, both `AGENTS.md`
   anchors plus its "never claim a later version" guard, `VERSION-PLAN.md` (header
@@ -292,7 +299,8 @@ cycle-accurate core later replaced.
   sync; the next is **v2.5.0**. A **licence change overrides and syncs
   immediately** — the rule that incident produced in the first place.
 
-- **`to-dos/DEFERRED-AND-CARRYOVER-FEATURES.md` swept entry by entry**, against
+- **`to-dos/DEFERRED-AND-CARRYOVER-FEATURES.md` swept entry by entry** (landed
+  between v2.4.0 and v2.4.1; part of neither), against
   `main` @ `fdfb2c04`. Eleven entries struck, each carrying its evidence inline —
   a file that exists, a workflow line number, a test that says so — rather than a
   bare tick, so a closure can be disagreed with.
diff --git a/Cargo.lock b/Cargo.lock
index 0fde6588..3977bc77 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4290,7 +4290,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-android"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "android-activity",
  "android_logger",
@@ -4308,7 +4308,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-apu"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "bitflags 2.13.1",
  "criterion",
@@ -4321,7 +4321,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-cheevos"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "cc",
  "ureq",
@@ -4329,7 +4329,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-core"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "bitflags 2.13.1",
  "criterion",
@@ -4346,7 +4346,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-cpu"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "bitflags 2.13.1",
  "criterion",
@@ -4357,7 +4357,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-frontend"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "anstyle",
  "arboard",
@@ -4416,18 +4416,18 @@ dependencies = [
 
 [[package]]
 name = "rustynes-gamedb"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "rustynes-core",
 ]
 
 [[package]]
 name = "rustynes-gfx-shaders"
-version = "2.3.9"
+version = "2.4.1"
 
 [[package]]
 name = "rustynes-hdpack"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "lewton",
  "png",
@@ -4438,7 +4438,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-ios"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "bytemuck",
  "cpal",
@@ -4452,7 +4452,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-libretro"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "libc",
  "rust-libretro",
@@ -4461,7 +4461,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-mappers"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "bitflags 2.13.1",
  "criterion",
@@ -4473,7 +4473,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-mobile"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "rustynes-core",
  "rustynes-hdpack",
@@ -4488,7 +4488,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-netplay"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "futures-util",
  "js-sys",
@@ -4504,7 +4504,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-ppu"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "bitflags 2.13.1",
  "criterion",
@@ -4516,21 +4516,21 @@ dependencies = [
 
 [[package]]
 name = "rustynes-probe"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "rustynes-core",
 ]
 
 [[package]]
 name = "rustynes-ra"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "rustynes-cheevos",
 ]
 
 [[package]]
 name = "rustynes-script"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "mlua",
  "piccolo",
@@ -4541,7 +4541,7 @@ dependencies = [
 
 [[package]]
 name = "rustynes-test-harness"
-version = "2.3.9"
+version = "2.4.1"
 dependencies = [
  "insta",
  "png",
diff --git a/Cargo.toml b/Cargo.toml
index d4cc6dac..5561920e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -77,7 +77,7 @@ default-members = ["crates/rustynes-libretro"]
 # `release-auto.yml` reads the `## [X.Y.Z]` line for BOTH the release body
 # fallback and the title codename — so the date and quoted codename are load-
 # bearing, not decoration.
-version = "2.3.9"
+version = "2.4.1"
 edition = "2024"
 rust-version = "1.96"
 license = "GPL-3.0-or-later"
diff --git a/OVERVIEW.md b/OVERVIEW.md
index b2612611..e46e0d8e 100644
--- a/OVERVIEW.md
+++ b/OVERVIEW.md
@@ -2,7 +2,7 @@
 
 **Document Version:** 2.1.0
 **Last Updated:** 2026-08-20
-**Applies to:** RustyNES v2.3.9
+**Applies to:** RustyNES v2.4.1
 
 ---
 
@@ -22,9 +22,9 @@
 
 RustyNES is the **definitive NES emulator for the modern era** — combining cycle-perfect accuracy with a complete contemporary feature set and the safety guarantees of Rust. It is more than an emulator: it is a platform for NES preservation, competitive online play, tool-assisted speedrunning, and homebrew development.
 
-As of **v1.0.0**, that vision was realized: RustyNES clears the Mesen2 / higan / ares accuracy bar, ships a polished desktop application and a browser build, and supports the full platform surface — netplay, achievements, TAS movies, a debugger, FDS, and arcade (Vs. / PlayChoice-10) hardware. Since then the additive v1.x line added three more platforms (native Android, iOS / iPadOS, and a Libretro / RetroArch core), **v2.0.0 "Timebase"** replaced the scheduler substrate with the one-clock / every-cycle-bus-access model (ADR 0029 — the one deliberate breaking release), and the v2.1.x → v2.3.x lines deepened accuracy, presentation, and analysis tooling. The current release is **v2.3.9 "Crucible"**.
+As of **v1.0.0**, that vision was realized: RustyNES clears the Mesen2 / higan / ares accuracy bar, ships a polished desktop application and a browser build, and supports the full platform surface — netplay, achievements, TAS movies, a debugger, FDS, and arcade (Vs. / PlayChoice-10) hardware. Since then the additive v1.x line added three more platforms (native Android, iOS / iPadOS, and a Libretro / RetroArch core), **v2.0.0 "Timebase"** replaced the scheduler substrate with the one-clock / every-cycle-bus-access model (ADR 0029 — the one deliberate breaking release), and the v2.1.x → v2.3.x lines deepened accuracy, presentation, and analysis tooling. The current release is **v2.4.1 "Fabric"**, which also carries the never-tagged v2.4.0 "Concordance".
 
-> RustyNES's emulation core descends from an extensively-documented accuracy program. Where this and related docs reference deep "v1.x"/"v2.x" engine narrative, read it as upstream engine lineage (engineering history), not as RustyNES release versions. Two distinct "v2.0"s exist and must not be conflated: the engine-lineage v2.0 master-clock work shipped as RustyNES **v1.0.0**, while RustyNES's own **v2.0.0 "Timebase"** (2026-07-03) is the later release that *replaced* that same scheduler. The current release is **v2.3.9**.
+> RustyNES's emulation core descends from an extensively-documented accuracy program. Where this and related docs reference deep "v1.x"/"v2.x" engine narrative, read it as upstream engine lineage (engineering history), not as RustyNES release versions. Two distinct "v2.0"s exist and must not be conflated: the engine-lineage v2.0 master-clock work shipped as RustyNES **v1.0.0**, while RustyNES's own **v2.0.0 "Timebase"** (2026-07-03) is the later release that *replaced* that same scheduler. The current release is **v2.4.1**.
 
 ---
 
diff --git a/README.md b/README.md
index b516e672..d31c50fe 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@
 </p>
 
 <p align="center">
-  <a href="https://github.com/doublegate/RustyNES/actions"><img src="https://github.com/doublegate/RustyNES/workflows/CI/badge.svg" alt="Build Status"></a> <a href="#license"><img src="https://img.shields.io/badge/license-GPL--3.0--or--later-blue.svg" alt="License: GPL-3.0-or-later"></a> <a href="https://github.com/doublegate/RustyNES/releases"><img src="https://img.shields.io/badge/version-v2.3.9-blue.svg" alt="Version"></a> <a href="rust-toolchain.toml"><img src="https://img.shields.io/badge/rust-1.96-orange.svg" alt="Rust: 1.96"></a><br>
+  <a href="https://github.com/doublegate/RustyNES/actions"><img src="https://github.com/doublegate/RustyNES/workflows/CI/badge.svg" alt="Build Status"></a> <a href="#license"><img src="https://img.shields.io/badge/license-GPL--3.0--or--later-blue.svg" alt="License: GPL-3.0-or-later"></a> <a href="https://github.com/doublegate/RustyNES/releases"><img src="https://img.shields.io/badge/version-v2.4.1-blue.svg" alt="Version"></a> <a href="rust-toolchain.toml"><img src="https://img.shields.io/badge/rust-1.96-orange.svg" alt="Rust: 1.96"></a><br>
   <a href="#compatibility-and-accuracy"><img src="https://img.shields.io/badge/AccuracyCoin-100%25%20(141%2F141)-brightgreen.svg" alt="AccuracyCoin"></a> <a href="#compatibility-and-accuracy"><img src="https://img.shields.io/badge/nestest-0--diff-brightgreen.svg" alt="nestest"></a> <a href="https://doublegate.github.io/RustyNES/"><img src="https://img.shields.io/badge/play-in%20browser-success.svg" alt="Try in browser"></a><br>
   <a href="#platform-support"><img src="https://img.shields.io/badge/platform-Windows%20%7C%20Linux%20%7C%20macOS%20%7C%20Web%20%7C%20Android%20%7C%20iOS-lightgrey.svg" alt="Platform"></a>
 </p>
@@ -668,9 +668,43 @@ and the Material-for-MkDocs documentation handbook at
 
 ## Current Release
 
-RustyNES's current release is **v2.3.9 "Crucible"** — a crucible tests to
-destruction rather than inspects, and that is what this release does to the
-project's own gates: what they cover, what they only *appear* to cover, and where
+RustyNES's current release is **v2.4.1 "Fabric"**, which opens the
+**v2.4.1 → v2.5.0 "Fabric"** line: a new NES core written in SystemVerilog from
+public hardware documentation, in a sibling repository, with this emulator as its
+**verification oracle**. RustyNES is not being ported to FPGA and cannot be — a
+MiSTer core is SystemVerilog compiled into a Cyclone V bitstream, and Rust does
+not become one. What is buildable is a *new* implementation verified against this
+one, and `crates/rustynes-cosim` is the boundary between them: a narrow C ABI a
+Verilator testbench links, plus a `nes_golden_export` CLI emitting the five golden
+formats an external implementation is compared against. The provenance firewall
+extends to HDL accordingly — `NES_MiSTer` and `fpganes` `rtl/` are strict black
+boxes, instantiable as opaque modules to compare *outputs*, never readable as
+source.
+
+**The crate is excluded from the workspace, and that is the load-bearing detail.**
+It enables `cpu-boot-trace` and `irq-timing-trace` on the core, and cargo unifies
+features across a workspace build — so as a member it made `cargo build
+--workspace` compile the core once with the union. `irq-timing-trace` selects a
+*different* per-dot loop in `Bus::tick_one_cpu_cycle`, so CI's accuracy battery
+was validating a scheduler no user runs. The measured cost was **+1.2% to +1.9%**,
+*below* this project's own 3% bar — published precisely because it shows
+performance was never the argument. Two more findings came out of building it:
+**the first `run_frame()` after power-on advances zero cycles** (the reset
+sequence leaves `frame_complete` latched, so a bare loop emits an (n−1)-frame
+golden under a manifest claiming n), and **no CI invocation had ever linted the
+two trace-gated core modules**, which held six pre-existing findings.
+
+This release also carries **v2.4.0 "Concordance"**, which merged to `main` and was
+never tagged: every path that persists user data now writes atomically and
+durably — including save states, where a truncated write is a user's game
+progress — plus a session-local timeline generation counter, and a standing
+audit pinning **15 release anchors across 10 documents** to the workspace version.
+`rustynes-core` changes in both halves, so the accuracy contract is **verified,
+not asserted**: AccuracyCoin **141/141 (100.00%)** on the authoritative RAM
+decoder, nestest 0-diff.
+
+Built on **v2.3.9 "Crucible"** — a crucible tests to destruction rather than
+inspects, and that is what that release did to the project's own gates: what they cover, what they only *appear* to cover, and where
 a regression could still reach `main` unchallenged. The v2.3.x line added five
 tools in four releases, and the recurring finding across all of them was never
 that the emulation was wrong. It was that **a check reported a pass it had not
diff --git a/ROADMAP.md b/ROADMAP.md
index 062b748b..1a5497a4 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -2,13 +2,13 @@
 
 **Document Version:** 2.0.4
 **Last Updated:** 2026-07-08
-**Project Status:** v2.3.9 "Crucible" released — the current head of the line, on the v2.0.0 "Timebase" MAJOR cut. **This file is a historical snapshot of the v1.0.0 cut**; see [`to-dos/ROADMAP.md`](to-dos/ROADMAP.md) for the authoritative forward roadmap and [`docs/STATUS.md`](docs/STATUS.md) for current state.
+**Project Status:** v2.4.1 "Fabric" released — the current head of the line, on the v2.0.0 "Timebase" MAJOR cut. **This file is a historical snapshot of the v1.0.0 cut**; see [`to-dos/ROADMAP.md`](to-dos/ROADMAP.md) for the authoritative forward roadmap and [`docs/STATUS.md`](docs/STATUS.md) for current state.
 
 ---
 
 ## Where we are
 
-RustyNES is well past v1.0.0. The current release is **v2.3.9 "Crucible"** (2026-08-20) — the gates release, sitting atop **v2.0.0 "Timebase"** (2026-07-03), the designated MAJOR cut that replaced the PPU-dot lockstep scheduler with the one-clock / every-cycle-bus-access model. Since then the **v2.0.x "Harbor"** mobile-finalization train, the **v2.1.x "Fathom"** accuracy line, the **v2.2.0 "Capstone"** milestone, the **v2.2.6 → v2.3.0** de-monetization + NESdev-remediation line, and the **v2.3.1 → v2.3.9** measurement / tooling / gates line have all shipped. Between v1.0.0 and v2.0.0 the additive v1.x line delivered deep desktop tooling and three whole new platforms (native Android, iOS / iPadOS, and a Libretro / RetroArch core); the v2.0.x train then re-ported mobile onto the new core and, at **v2.0.3**, promoted the 2-cycle-ALE PPU fetch model to the default to reach **AccuracyCoin 100% (141/141)**.
+RustyNES is well past v1.0.0. The current release is **v2.4.1 "Fabric"** (2026-08-20) — the oracle release opening the v2.4.1 → v2.5.0 "Fabric" line, and carrying the never-tagged v2.4.0 "Concordance", sitting atop **v2.0.0 "Timebase"** (2026-07-03), the designated MAJOR cut that replaced the PPU-dot lockstep scheduler with the one-clock / every-cycle-bus-access model. Since then the **v2.0.x "Harbor"** mobile-finalization train, the **v2.1.x "Fathom"** accuracy line, the **v2.2.0 "Capstone"** milestone, the **v2.2.6 → v2.3.0** de-monetization + NESdev-remediation line, and the **v2.3.1 → v2.3.9** measurement / tooling / gates line have all shipped. Between v1.0.0 and v2.0.0 the additive v1.x line delivered deep desktop tooling and three whole new platforms (native Android, iOS / iPadOS, and a Libretro / RetroArch core); the v2.0.x train then re-ported mobile onto the new core and, at **v2.0.3**, promoted the 2-cycle-ALE PPU fetch model to the default to reach **AccuracyCoin 100% (141/141)**.
 
 **This root ROADMAP is a historical snapshot of the v1.0.0 cut.** For the authoritative, current forward roadmap see **[`to-dos/ROADMAP.md`](to-dos/ROADMAP.md)**; for the authoritative current-state pass counts and platform matrix see **[`docs/STATUS.md`](docs/STATUS.md)**; for the full per-release history see **[`CHANGELOG.md`](CHANGELOG.md)**. Many of the "post-1.0 directions" listed further down (mobile, Lua scripting, TAS editor, Vs. DualSystem, HD packs, hosted netplay) have since shipped — the tables below record what was **done at v1.0.0**, not the current feature set.
 
diff --git a/SECURITY.md b/SECURITY.md
index a75ab8fb..ba89f614 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -2,7 +2,7 @@
 
 ## Supported Versions
 
-The current release is **v2.3.9 "Crucible"**. RustyNES ships from `main` on a
+The current release is **v2.4.1 "Fabric"**, which also carries the never-tagged v2.4.0 "Concordance". RustyNES ships from `main` on a
 rolling patch cadence rather than maintaining long-lived release branches, so
 security fixes land in the next patch release rather than being backported.
 Report against the latest release or `main`.
diff --git a/SUPPORT.md b/SUPPORT.md
index b46153ac..2237ec60 100644
--- a/SUPPORT.md
+++ b/SUPPORT.md
@@ -94,7 +94,7 @@ A: RustyNES is a cycle-accurate NES emulator written in pure Rust, clearing the
 
 **Q: Can I use RustyNES now?**
 
-A: Yes. RustyNES is well past its first stable release — the current release is **v2.3.9 "Crucible"** (the gates release, on the v2.0.0 "Timebase" one-clock scheduler base), a complete, playable desktop application plus native Android / iOS / Libretro builds and a browser build. See [`to-dos/ROADMAP.md`](to-dos/ROADMAP.md) for what shipped and the forward directions.
+A: Yes. RustyNES is well past its first stable release — the current release is **v2.4.1 "Fabric"** (the oracle release opening the v2.4.1 → v2.5.0 "Fabric" line, and carrying the never-tagged v2.4.0 "Concordance", on the v2.0.0 "Timebase" one-clock scheduler base), a complete, playable desktop application plus native Android / iOS / Libretro builds and a browser build. See [`to-dos/ROADMAP.md`](to-dos/ROADMAP.md) for what shipped and the forward directions.
 
 **Q: How accurate is RustyNES?**
 
diff --git a/VERSION-PLAN.md b/VERSION-PLAN.md
index 1dc6c66b..370589c7 100644
--- a/VERSION-PLAN.md
+++ b/VERSION-PLAN.md
@@ -1,6 +1,6 @@
 # RustyNES Version Plan
 
-**Current release: v2.3.9 "Crucible"** — what the gates actually cover. A crucible tests to destruction rather than inspects, and this release does that to the project's own checks. **The docs-only CI skip had never worked**: `predicate-quantifier` defaults to `some`, so the `code` filter's leading `'**'` matched everything and all seven `!` exclusions under it were dead from the day they were written — fixed with **two** filter steps, because the quantifier is step-level and `accuracy` is a list of *alternatives* that becomes unsatisfiable under `every`, so the one-line fix would have silently disabled the accuracy battery while repairing a different gate. **`test-roms` now runs at review time**, path-filtered over the chip crates, the core, `rustynes-gamedb`, the harness and `tests/` (11 of the last 40 merged PRs, so ~72% still pay nothing). **A freeze from one cartridge kept writing into the next** — an active per-frame write into the wrong game — closed by a ROM-transition sweep across every panel under one rule: derived output discarded, user-authored input kept, and only input that actively *writes* neutralised. **The config file is written atomically and durably** (seven properties, five from review rather than the first draft). Plus 257 lines of dead code removed, 25 of 29 `#[allow(dead_code)]` attributes found to suppress nothing, `undocumented_unsafe_blocks` made a gate, and two `cargo deny` ignores retired on their own stated condition. `rustynes-apu` and `rustynes-core` both change, so **AccuracyCoin 141/141 and nestest 0-diff are verified, not asserted**. Built on **v2.3.8 "Parallax"** — which pixels differ, not just which frame: `Probe` could say two configurations of the same ROM diverge and *at which frame* and nothing about where or why, because a trial reduces each frame to one `u64`. The **Divergence Lens** keeps the full output instead of its hash and reports the *shape* of the difference (population count, first pixel in raster order, inclusive bounding box), localises on the **index** framebuffer so a palette difference cannot masquerade as a rendering one, hands the located pixel to Pixel Provenance so the answer is a cause rather than a coordinate, and answers `Inconclusive` rather than letting "I stopped looking" wear the shape of "they agree". Built on **v2.3.7 "Overtone"** — the audio-provenance release: a per-register write attribution (*what wrote this, and from which instruction*) plus a per-CPU-cycle mix trace, and the discovery that Pixel Provenance had shipped non-functional for four releases because run-ahead's rollback cleared its store before any UI could read it — in three more places than the v2.3.6 fix had enumerated. Built on **v2.3.6 "Sounding"** — measuring, and what a measurement may claim. Two shipped features are found never to have worked: **Pixel Provenance** returned an empty report for every user on the default `run_ahead = 1` (its rollback is the last thing before the frontend takes the lock, so the panel always looked after the wipe) and "click any pixel" was never implemented — two comments and four doc claims asserted the opposite of their own code, which is why four releases passed unchecked; and **Duck Hunt could never score**, its Zapper probe exactly inverting the "see nothing, then a bright spot" protocol. Two new tools built to **decline rather than guess**: the **Latency Oracle** (measures the game's own input lag; recommends a run-ahead depth and never applies one) and the **RAM Atlas** (classifies all 2 KiB of work RAM, then *verifies* a candidate by perturbing it — `Untested` is a third state distinct from `Inert`, and liveness names its lens). **APU Workstream D is closed** on three measured rejections plus the fat-LTO mechanism explaining them. Tools and Debug are regrouped by task. Core gains one `const fn` getter, so AccuracyCoin 141/141 is verified, not asserted. Built on **v2.3.5 "Manifest"** — the declaration release: what the core says about itself. A user reported RetroArch still showing the pre-relicense MIT/Apache-2.0 terms, and it was: RetroArch reads `dist/info/` from **libretro/libretro-super**, a SEPARATE copy nothing synced, so the v2.2.9 GPL relicense never reached the file users see. Corrected to `GPLv3+` with a standing `libretro_info_audit.rs` that makes the upstream sync a **copy** rather than a re-derivation, and a licence change is now a mandatory upstream-sync trigger. Auditing the wrapper then found **five further defects, every one with correct emulation behind it** — PAL ran 20.2% fast, Reset did nothing ever, unload leaked Game Genie indices, the aspect ratio assumed square pixels, and the Zapper was unreachable — plus a **use-after-free** in the controller tables caught in review. The crate went from zero tests to eight. The APU also gained its first throughput bench and a default-configuration mix specialization (−3.3% to −4.2% on `nes_run_frame_nestest`), so **AccuracyCoin 141/141 was VERIFIED, not asserted**. Built on **v2.3.4 "Ledger"** — the coverage release: three boards (mapper 176 submapper 2 WAIXING-FS005, 154 NAMCOT-3453, 243 Sachen SA-020A, breadth **172 → 174 families**), the coverage harness moved onto the frontend's real load path, and the defect that exposed — the per-game database reading a `0` Mapper column as "force NROM" and overwriting correct headers, leaving **every Sachen cartridge** unloadable since **v1.2.0**. **This release touches the emulation core**, so AccuracyCoin exactly 141/141 is **verified, not asserted by construction**. Its Workstream C (the APU at 18.7% of frame time) was carried to v2.3.5 and delivered there. Built on **v2.3.3 "Cadence"** — the display-pacing release: the run-ahead throttle oscillation traced to a stale median (a gate counting 120 frames of a 600-sample ring), a predictive engage arm that converges a `run_ahead = 3` host in 2.8 s instead of 12.1 s, and the `wp_presentation` measurement apparatus that made the diagnosis possible. **No emulation-core changes** (AccuracyCoin exactly 141/141). Built on **v2.3.2 "Lucid"** (pixel provenance + deterministic replay attestation), **v2.3.1 "Plumb Line"** (ten measured rejections), and **v2.3.0 "Datum II"**, the capstone that **closed** the v2.2.6 → v2.3.0 line (true multi-viewport OS-window detach, the emulator-lock frame-pacing fix, a −5.1% byte-identical PPU optimization, and both forum-reported accuracy items verified already-correct) — all on the **v2.0.0 "Timebase"** MAJOR base (the one-clock / every-cycle-bus-access scheduler rewrite). **v1.0.0** was the first stable, production cut. As of **v2.2.9**, RustyNES is **GPL-3.0-or-later** — a derivative work of GPL-licensed emulators (ADR 0036); a licensing correction, **not** a SemVer break (no public-API or save-state change). `docs/STATUS.md` is the authoritative current-state record; `CHANGELOG.md` carries the full per-release history.
+**Current release: v2.4.1 "Fabric"** — RustyNES as the oracle a new implementation is verified against. It opens the **v2.4.1 → v2.5.0 "Fabric"** line: a new NES core in SystemVerilog, written from public hardware documentation in a sibling repository, with this emulator as its verification oracle. RustyNES is not being ported to FPGA and cannot be; `crates/rustynes-cosim` is the boundary, and the firewall extends to HDL (ADR 0037). **v2.5.0 is scoped to "the 6502 rung closes"**, not a finished core. Excluding the crate from the workspace is the load-bearing detail — cargo unifies features, and `irq-timing-trace` selects a *different* per-dot loop in `Bus::tick_one_cpu_cycle`, so the accuracy battery had been validating a scheduler no user runs. It also carries **v2.4.0 "Concordance"**, which merged to `main` and was never tagged: atomic durable writes on every path that persists user data, `Nes::timeline_generation()`, and the 15-anchor release audit. AccuracyCoin **141/141** and nestest 0-diff verified, not asserted. Previously, **v2.3.9 "Crucible"** — what the gates actually cover. A crucible tests to destruction rather than inspects, and this release does that to the project's own checks. **The docs-only CI skip had never worked**: `predicate-quantifier` defaults to `some`, so the `code` filter's leading `'**'` matched everything and all seven `!` exclusions under it were dead from the day they were written — fixed with **two** filter steps, because the quantifier is step-level and `accuracy` is a list of *alternatives* that becomes unsatisfiable under `every`, so the one-line fix would have silently disabled the accuracy battery while repairing a different gate. **`test-roms` now runs at review time**, path-filtered over the chip crates, the core, `rustynes-gamedb`, the harness and `tests/` (11 of the last 40 merged PRs, so ~72% still pay nothing). **A freeze from one cartridge kept writing into the next** — an active per-frame write into the wrong game — closed by a ROM-transition sweep across every panel under one rule: derived output discarded, user-authored input kept, and only input that actively *writes* neutralised. **The config file is written atomically and durably** (seven properties, five from review rather than the first draft). Plus 257 lines of dead code removed, 25 of 29 `#[allow(dead_code)]` attributes found to suppress nothing, `undocumented_unsafe_blocks` made a gate, and two `cargo deny` ignores retired on their own stated condition. `rustynes-apu` and `rustynes-core` both change, so **AccuracyCoin 141/141 and nestest 0-diff are verified, not asserted**. Built on **v2.3.8 "Parallax"** — which pixels differ, not just which frame: `Probe` could say two configurations of the same ROM diverge and *at which frame* and nothing about where or why, because a trial reduces each frame to one `u64`. The **Divergence Lens** keeps the full output instead of its hash and reports the *shape* of the difference (population count, first pixel in raster order, inclusive bounding box), localises on the **index** framebuffer so a palette difference cannot masquerade as a rendering one, hands the located pixel to Pixel Provenance so the answer is a cause rather than a coordinate, and answers `Inconclusive` rather than letting "I stopped looking" wear the shape of "they agree". Built on **v2.3.7 "Overtone"** — the audio-provenance release: a per-register write attribution (*what wrote this, and from which instruction*) plus a per-CPU-cycle mix trace, and the discovery that Pixel Provenance had shipped non-functional for four releases because run-ahead's rollback cleared its store before any UI could read it — in three more places than the v2.3.6 fix had enumerated. Built on **v2.3.6 "Sounding"** — measuring, and what a measurement may claim. Two shipped features are found never to have worked: **Pixel Provenance** returned an empty report for every user on the default `run_ahead = 1` (its rollback is the last thing before the frontend takes the lock, so the panel always looked after the wipe) and "click any pixel" was never implemented — two comments and four doc claims asserted the opposite of their own code, which is why four releases passed unchecked; and **Duck Hunt could never score**, its Zapper probe exactly inverting the "see nothing, then a bright spot" protocol. Two new tools built to **decline rather than guess**: the **Latency Oracle** (measures the game's own input lag; recommends a run-ahead depth and never applies one) and the **RAM Atlas** (classifies all 2 KiB of work RAM, then *verifies* a candidate by perturbing it — `Untested` is a third state distinct from `Inert`, and liveness names its lens). **APU Workstream D is closed** on three measured rejections plus the fat-LTO mechanism explaining them. Tools and Debug are regrouped by task. Core gains one `const fn` getter, so AccuracyCoin 141/141 is verified, not asserted. Built on **v2.3.5 "Manifest"** — the declaration release: what the core says about itself. A user reported RetroArch still showing the pre-relicense MIT/Apache-2.0 terms, and it was: RetroArch reads `dist/info/` from **libretro/libretro-super**, a SEPARATE copy nothing synced, so the v2.2.9 GPL relicense never reached the file users see. Corrected to `GPLv3+` with a standing `libretro_info_audit.rs` that makes the upstream sync a **copy** rather than a re-derivation, and a licence change is now a mandatory upstream-sync trigger. Auditing the wrapper then found **five further defects, every one with correct emulation behind it** — PAL ran 20.2% fast, Reset did nothing ever, unload leaked Game Genie indices, the aspect ratio assumed square pixels, and the Zapper was unreachable — plus a **use-after-free** in the controller tables caught in review. The crate went from zero tests to eight. The APU also gained its first throughput bench and a default-configuration mix specialization (−3.3% to −4.2% on `nes_run_frame_nestest`), so **AccuracyCoin 141/141 was VERIFIED, not asserted**. Built on **v2.3.4 "Ledger"** — the coverage release: three boards (mapper 176 submapper 2 WAIXING-FS005, 154 NAMCOT-3453, 243 Sachen SA-020A, breadth **172 → 174 families**), the coverage harness moved onto the frontend's real load path, and the defect that exposed — the per-game database reading a `0` Mapper column as "force NROM" and overwriting correct headers, leaving **every Sachen cartridge** unloadable since **v1.2.0**. **This release touches the emulation core**, so AccuracyCoin exactly 141/141 is **verified, not asserted by construction**. Its Workstream C (the APU at 18.7% of frame time) was carried to v2.3.5 and delivered there. Built on **v2.3.3 "Cadence"** — the display-pacing release: the run-ahead throttle oscillation traced to a stale median (a gate counting 120 frames of a 600-sample ring), a predictive engage arm that converges a `run_ahead = 3` host in 2.8 s instead of 12.1 s, and the `wp_presentation` measurement apparatus that made the diagnosis possible. **No emulation-core changes** (AccuracyCoin exactly 141/141). Built on **v2.3.2 "Lucid"** (pixel provenance + deterministic replay attestation), **v2.3.1 "Plumb Line"** (ten measured rejections), and **v2.3.0 "Datum II"**, the capstone that **closed** the v2.2.6 → v2.3.0 line (true multi-viewport OS-window detach, the emulator-lock frame-pacing fix, a −5.1% byte-identical PPU optimization, and both forum-reported accuracy items verified already-correct) — all on the **v2.0.0 "Timebase"** MAJOR base (the one-clock / every-cycle-bus-access scheduler rewrite). **v1.0.0** was the first stable, production cut. As of **v2.2.9**, RustyNES is **GPL-3.0-or-later** — a derivative work of GPL-licensed emulators (ADR 0036); a licensing correction, **not** a SemVer break (no public-API or save-state change). `docs/STATUS.md` is the authoritative current-state record; `CHANGELOG.md` carries the full per-release history.
 
 RustyNES follows [Semantic Versioning 2.0.0](https://semver.org/).
 
@@ -85,7 +85,9 @@ The 1.x line was **additive / off-by-default** — every release stayed byte-ide
 | **v2.3.6 "Sounding"** | Measuring, and what a measurement may claim. **Two shipped features found never to have worked**: Pixel Provenance returned an empty report for every user on the default `run_ahead = 1` (rollback is the last thing before the frontend releases the lock, so the panel always looked *after* the wipe) and "click any pixel" was never implemented — two source comments and four doc claims asserted the opposite of their own code, which is why four releases passed unchecked; and **Duck Hunt could never score**, its Zapper probe exactly inverting the "see nothing, then a bright spot" protocol. Two new tools built to **decline rather than guess**: the **Latency Oracle** (recommends a run-ahead depth and never applies one; `None` and `Some(0)` never collapsed) and the **RAM Atlas** (observation returns all 2048 labels `Untested`, so it is *structurally* incapable of claiming an effect). **APU Workstream D closed** on three measured rejections plus the fat-LTO mechanism that explains them. Core gains one `const fn` getter, so AccuracyCoin 141/141 is **verified** — see `CHANGELOG.md` `[2.3.6]` |
 | **v2.3.7 "Overtone"** | Audio provenance — the APU counterpart of Pixel Provenance: a per-register write attribution (*what wrote this, and from which instruction*) and a per-CPU-cycle mix trace carrying **raw** pre-mix channel values, so a record describes the chip rather than the user's mixer sliders. Its real subject is the trap it inherited: the v2.3.6 fix had enumerated **one caller** rather than the mechanism, and `rustynes-probe` had **three more** same-timeline restores, so running the Latency Oracle or the RAM Atlas emptied both provenance panels for the session. The test named for the contract compared `nes.snapshot()`, and provenance is deliberately not in the snapshot — it asserted something strictly weaker than its own name and passed throughout. A randomized sweep of the save-state parse boundary found **four** panics in VRC7's OPLL where hand-tracing found one; the all-`0xFF` payload *concealed* one. Both core crates change, so AccuracyCoin 141/141 is **verified** — see `CHANGELOG.md` `[2.3.7]` |
 | **v2.3.8 "Parallax"** | The **Divergence Lens** — which pixels differ, not just which frame. A trial reduces each frame to one `u64`: the right shape for *detecting* a difference and the wrong shape for *explaining* one. `divergence::localise` keeps the full output and reports the *shape* — population count, first pixel in raster order, inclusive bounding box — on the **index** framebuffer (the PPU's own per-pixel output before the palette lookup), then hands the located pixel to Pixel Provenance so the answer is a cause rather than a coordinate. Three verdicts, and the third is the point: **`Inconclusive`** never arrives wearing the shape of `Identical`. Cut from its own boundary commit rather than from `main`, so its artifacts contain exactly the Lens — see `CHANGELOG.md` `[2.3.8]` |
-| **v2.3.9 "Crucible"** (current) | What the gates actually cover. **The docs-only CI skip had never worked** — `predicate-quantifier` defaults to `some`, so the `code` filter's leading `'**'` matched everything and all seven `!` exclusions were dead from the day they were written; fixed with **two** filter steps because `accuracy` is a list of *alternatives* that becomes unsatisfiable under `every`. **`test-roms` now runs at review time** (path-filtered; 11 of the last 40 merged PRs). **A freeze from one cartridge kept writing into the next**, closed by a ROM-transition sweep under one rule: derived output discarded, user-authored input kept, and only input that actively *writes* neutralised. **The config file is written atomically and durably** (seven properties, five from review). 257 lines of dead code removed; 25 of 29 `#[allow(dead_code)]` attributes suppressed nothing; `undocumented_unsafe_blocks` made a gate. Both core crates change, so AccuracyCoin 141/141 is **verified** — see `CHANGELOG.md` `[2.3.9]` |
+| **v2.3.9 "Crucible"** | What the gates actually cover. **The docs-only CI skip had never worked** — `predicate-quantifier` defaults to `some`, so the `code` filter's leading `'**'` matched everything and all seven `!` exclusions were dead from the day they were written; fixed with **two** filter steps because `accuracy` is a list of *alternatives* that becomes unsatisfiable under `every`. **`test-roms` now runs at review time** (path-filtered; 11 of the last 40 merged PRs). **A freeze from one cartridge kept writing into the next**, closed by a ROM-transition sweep under one rule: derived output discarded, user-authored input kept, and only input that actively *writes* neutralised. **The config file is written atomically and durably** (seven properties, five from review). 257 lines of dead code removed; 25 of 29 `#[allow(dead_code)]` attributes suppressed nothing; `undocumented_unsafe_blocks` made a gate. Both core crates change, so AccuracyCoin 141/141 is **verified** — see `CHANGELOG.md` `[2.3.9]` |
+| **v2.4.0 "Concordance"** (merged, never tagged; shipped inside v2.4.1) | Atomic, durable writes on every path that persists user data — the plan named three call sites and there were **four**, the fourth being `save_state.rs`, where a truncated write is a user's game progress, while `per_game.rs` was not in the plan at all because it *looks* correct and held two of seven properties. Review found **four more silent successes**, each an error discarded under a comment explaining the rest of the operation. Plus `Nes::timeline_generation()` (session-local, deliberately not in the save state) and `release_anchor_audit.rs`, pinning **15 release anchors across 10 documents**. |
+| **v2.4.1 "Fabric"** (current) | RustyNES as the oracle a new implementation is verified against, opening the v2.4.1 → v2.5.0 "Fabric" line. `crates/rustynes-cosim` exposes the emulator through a narrow C ABI a Verilator testbench links, plus `nes_golden_export`. **Excluding it from the workspace is the load-bearing detail**: cargo unifies features, `irq-timing-trace` selects a *different* per-dot loop in `Bus::tick_one_cpu_cycle`, and the accuracy battery had therefore been validating a scheduler no user runs (+1.2% to +1.9%, below the 3% bar — the percentage was never the argument). Also: the first `run_frame()` after power-on advances **zero** cycles, and two trace-gated core modules had never been linted. Carries v2.4.0. AccuracyCoin 141/141 verified. |
 
 > **Forward path.** The v2.0.x "Harbor", v2.1.x "Fathom", and v2.2.x lines have all shipped; the v2.2.6 → v2.3.0 line has now **closed** with v2.3.0 "Datum II"; the v2.3.x performance campaign has now **shipped in full**, as three releases: **v2.3.1 "Plumb Line"** absorbed both the measurement apparatus and the core hot-path campaign, whose ten items were all measured and all rejected and so had no shippable content of their own; **v2.3.2 "Lucid"** the novel features (pixel provenance + replay attestation); and **v2.3.3 "Cadence"** the display-pacing work — the run-ahead throttle oscillation traced to a stale median, the predictive engage arm, and the `wp_presentation` measurement apparatus that made the diagnosis possible. The campaign closed there; **v2.3.4 "Ledger"** opened the next line with mapper coverage — three boards to **174 families**, and the coverage harness moved onto the frontend's real load path, which exposed a per-game-database defect that had left every Sachen cartridge unloadable since v1.2.0. Its Workstream C, the APU at 18.7% of frame time, was not delivered there and landed in **v2.3.5 "Manifest"**, which is otherwise about what the core declares about itself: the libretro `.info` licence drift a user reported, and the five wrapper defects auditing it uncovered. The line then continued as a **measurement-and-honesty** run rather than a feature one: **v2.3.6 "Sounding"** (two shipped features found never to have worked; the Latency Oracle and RAM Atlas both built to decline rather than guess), **v2.3.7 "Overtone"** (audio provenance, and the same-timeline-restore defect found in three more places than the v2.3.6 fix had enumerated), **v2.3.8 "Parallax"** (the Divergence Lens — which pixels differ, not just which frame), and **v2.3.9 "Crucible"** (current) — which turned the same scrutiny on the project's own gates and found a docs-only CI skip that had never worked, an accuracy battery that only ran after merge, and a freeze from one cartridge writing into the next. Note the codenames diverged from this plan as written: what shipped as v2.3.2 took "Lucid" rather than the planned "Grain"/"Conduit II", and v2.3.3 is "Cadence". RustyNES is **permanently open-source and income-free** (ADR 0035): the earlier "joint Google Play + App Store + AltStore + F-Droid launch" is **withdrawn** — any store listing is a **free** app with **no monetization** (no ads, tracking, or paid unlock), an unversioned later step. `to-dos/ROADMAP.md` is the authoritative forward roadmap.
 
diff --git a/crates/rustynes-cosim/Cargo.toml b/crates/rustynes-cosim/Cargo.toml
index 2e8a80c8..9487fb2d 100644
--- a/crates/rustynes-cosim/Cargo.toml
+++ b/crates/rustynes-cosim/Cargo.toml
@@ -8,7 +8,7 @@ description = "RustyNES as a co-simulation oracle for an external HDL device-und
 # The duplication is PINNED, not merely noticed: `cosim_manifest_audit.rs` in
 # `rustynes-test-harness` asserts these values still match the workspace's, so
 # drift fails a test instead of accumulating quietly.
-version = "2.3.9"
+version = "2.4.1"
 edition = "2024"
 rust-version = "1.96"
 license = "GPL-3.0-or-later"
diff --git a/crates/rustynes-libretro/rustynes_libretro.info b/crates/rustynes-libretro/rustynes_libretro.info
index c231a583..bc07b77c 100644
--- a/crates/rustynes-libretro/rustynes_libretro.info
+++ b/crates/rustynes-libretro/rustynes_libretro.info
@@ -5,7 +5,7 @@ supported_extensions = "nes|fds"
 corename = "RustyNES"
 license = "GPLv3+"
 permissions = ""
-display_version = "v2.3.9"
+display_version = "v2.4.1"
 categories = "Emulator"
 
 # Hardware Information
diff --git a/docs/STATUS.md b/docs/STATUS.md
index 567f9629..86b0ba9c 100644
--- a/docs/STATUS.md
+++ b/docs/STATUS.md
@@ -1,8 +1,34 @@
 # RustyNES — Project Status Matrix
 
-> **Current release: v2.3.9** (2026-08-20) — **"Crucible"**, what the gates
-> actually cover. A crucible tests to destruction rather than inspects, and this
-> release does that to the project's own checks: what they cover, what they only
+> **Current release: v2.4.1** (2026-08-20) — **"Fabric"**, RustyNES as the
+> oracle a new implementation is verified against. It opens the
+> **v2.4.1 → v2.5.0 "Fabric"** line: a new NES core in SystemVerilog, written
+> from public hardware documentation in a sibling repository, with this emulator
+> as its verification oracle. RustyNES is not being ported to FPGA and cannot be;
+> `crates/rustynes-cosim` is the boundary — a narrow C ABI a Verilator testbench
+> links, plus a `nes_golden_export` CLI. The firewall extends to HDL: `NES_MiSTer`
+> and `fpganes` `rtl/` are strict black boxes.
+>
+> **The crate is excluded from the workspace, and that is the load-bearing
+> detail.** Cargo unifies features across a workspace build, and this crate
+> enables `irq-timing-trace`, which selects a *different* per-dot loop in
+> `Bus::tick_one_cpu_cycle` — so CI's accuracy battery was validating a scheduler
+> no user runs. Measured cost **+1.2% to +1.9%**, below the project's own 3% bar,
+> which is why the percentage was never the argument. Also found while building
+> it: **the first `run_frame()` after power-on advances zero cycles**, and **two
+> trace-gated core modules had never been linted** (six pre-existing findings).
+>
+> It also carries **v2.4.0 "Concordance"**, which merged to `main` and was never
+> tagged: atomic, durable writes on every path that persists user data (four call
+> sites, and four further silent successes found in review), a session-local
+> `Nes::timeline_generation()` counter, and a standing audit pinning **15 release
+> anchors across 10 documents**. `rustynes-core` changes in both halves, so
+> **AccuracyCoin 141/141 (100.00%, RAM decoder) and nestest 0-diff are verified,
+> not asserted.**
+>
+> Built on **v2.3.9 "Crucible"** — what the gates actually cover. A crucible tests
+> to destruction rather than inspects, and that release did that to the project's
+> own checks: what they cover, what they only
 > *appear* to cover, and where a regression could still reach `main`
 > unchallenged. The v2.3.x line added five tools in four releases, and the
 > recurring finding across all of them was never that the emulation was wrong —
diff --git a/to-dos/ROADMAP.md b/to-dos/ROADMAP.md
index a6f2ba11..91c4d102 100644
--- a/to-dos/ROADMAP.md
+++ b/to-dos/ROADMAP.md
@@ -55,7 +55,7 @@ v2.8.0 → v0.9.7; the synthesis itself = **v1.0.0**.
 
 ## Status
 
-- **Current release:** **RustyNES v2.3.9 "Crucible"** (2026-08-20) — the **gates** release. A crucible tests to destruction rather than inspects, and that is what this release does to the project's own checks: what they cover, what they only *appear* to cover, and where a regression could still reach `main` unchallenged. The v2.3.x line added five tools in four releases, and the recurring finding across all of them was never that the emulation was wrong — it was that **a check reported a pass it had not earned**. **The docs-only CI skip had never worked**: `dorny/paths-filter`’s `predicate-quantifier` defaults to `some`, so the `code` filter’s leading `'**'` matched everything and all seven `!` exclusions under it were dead from the day they were written — a markdown-only PR logged `Filter code = true`. Fixed with **two** filter steps, because the quantifier is step-level and `accuracy` is a list of *alternatives* that becomes unsatisfiable under `every`: the naive one-line fix would have silently disabled the accuracy battery while repairing a different gate. **`test-roms` now runs at review time**, path-filtered over the chip crates, the core, `rustynes-gamedb`, the harness and `tests/` — measured first at 11 of the last 40 merged PRs, so ~72% still pay nothing. **A freeze from one cartridge kept writing into the next** — not a stale label but an active per-frame write into the wrong game, closed by a ROM-transition sweep across every panel under one rule: derived output is discarded, user-authored input is kept, and only input that actively *writes* is neutralised. **The config file is now written atomically and durably** (seven properties, five of them from review rather than the first draft). Plus **257 lines of dead code removed**, the SAFETY-comment rule made a clippy gate (`undocumented_unsafe_blocks`, demonstrated to fail), and two `cargo deny` advisory ignores retired on their own stated condition. `rustynes-apu` and `rustynes-core` both change, so **AccuracyCoin 141/141 (100.00%, RAM decoder) and nestest 0-diff are VERIFIED, not asserted.** **`docs/STATUS.md` is the authoritative current-state record.**
+- **Current release:** **RustyNES v2.4.1 "Fabric"** (2026-08-20) — the **oracle** release, opening the **v2.4.1 → v2.5.0 "Fabric"** line: a new NES core written in SystemVerilog from public hardware documentation, in a sibling repository, with this emulator as its **verification oracle**. RustyNES is not being ported to FPGA and cannot be; `crates/rustynes-cosim` is the boundary (a narrow C ABI a Verilator testbench links, plus `nes_golden_export`), and the provenance firewall extends to HDL per ADR 0037. **v2.5.0 is scoped to "the 6502 rung closes"**, not a finished core. Excluding the crate from the workspace is the load-bearing detail — cargo unifies features, `irq-timing-trace` selects a *different* per-dot loop in `Bus::tick_one_cpu_cycle`, and the accuracy battery had been validating a scheduler no user runs. It also carries **v2.4.0 "Concordance"**, which merged to `main` and was never tagged: atomic durable writes on every path that persists user data, `Nes::timeline_generation()`, and the 15-anchor release audit. AccuracyCoin **141/141** verified, not asserted. Built on **v2.3.9 "Crucible"** (2026-08-20) — the **gates** release. A crucible tests to destruction rather than inspects, and that is what this release does to the project's own checks: what they cover, what they only *appear* to cover, and where a regression could still reach `main` unchallenged. The v2.3.x line added five tools in four releases, and the recurring finding across all of them was never that the emulation was wrong — it was that **a check reported a pass it had not earned**. **The docs-only CI skip had never worked**: `dorny/paths-filter`’s `predicate-quantifier` defaults to `some`, so the `code` filter’s leading `'**'` matched everything and all seven `!` exclusions under it were dead from the day they were written — a markdown-only PR logged `Filter code = true`. Fixed with **two** filter steps, because the quantifier is step-level and `accuracy` is a list of *alternatives* that becomes unsatisfiable under `every`: the naive one-line fix would have silently disabled the accuracy battery while repairing a different gate. **`test-roms` now runs at review time**, path-filtered over the chip crates, the core, `rustynes-gamedb`, the harness and `tests/` — measured first at 11 of the last 40 merged PRs, so ~72% still pay nothing. **A freeze from one cartridge kept writing into the next** — not a stale label but an active per-frame write into the wrong game, closed by a ROM-transition sweep across every panel under one rule: derived output is discarded, user-authored input is kept, and only input that actively *writes* is neutralised. **The config file is now written atomically and durably** (seven properties, five of them from review rather than the first draft). Plus **257 lines of dead code removed**, the SAFETY-comment rule made a clippy gate (`undocumented_unsafe_blocks`, demonstrated to fail), and two `cargo deny` advisory ignores retired on their own stated condition. `rustynes-apu` and `rustynes-core` both change, so **AccuracyCoin 141/141 (100.00%, RAM decoder) and nestest 0-diff are VERIFIED, not asserted.** **`docs/STATUS.md` is the authoritative current-state record.**
 - **Next up — v2.4.0 "Concordance".** A concordance is an index of where every term actually occurs, and the release is scoped as one: reconcile what the project says about itself with what is true outside it. Four items, each traceable to a recorded deferral rather than newly invented — **(A)** the **owed upstream libretro sync** (`libretro-super` + `libretro/docs`), the one carried obligation with an outside deadline; **(B)** a core-side **timeline generation counter** replacing the last-seen-`cycle()` heuristic for stale telemetry (it covers a restore to a *later* state, which the heuristic cannot), deliberately **not** serialized, so it must land with its consumers and be AccuracyCoin-**verified**; **(C)** a **shared atomic-write helper**, lifting v2.3.9's seven properties out of `config.rs` and giving the Windows tail a real implementation rather than a portable spine; and **(D)** `skip_serializing_if` on `hd_packs` / `shader_presets`, which carry the same false byte-identity claim v2.3.9 corrected in prose only. Explicitly out of scope, and recorded as decisions rather than oversights: the remaining RAM Atlas exports (a cheat is a **write**, so it needs a locked-session predicate the watch export correctly does without), RAM Atlas per-game persistence (a restored verdict without its evidence is a claim that cannot be checked — this panel's whole argument in reverse), APU workstreams **D2 and D4** (unmeasured on purpose; their prior is a null, not an unknown), a CHANGELOG gate (**measured and rejected** — 62% false positives against the project's own history), and any store launch. See [`plans/v2.4.0-concordance-plan.md`](plans/v2.4.0-concordance-plan.md).
 - **Programme after v2.4.0 — the v2.4.1 → v2.5.0 "Fabric" line, and the v2.6–v2.9 programme behind it.** An **independently-written NES core in SystemVerilog for MiSTer FPGA and the Retro Remake SuperStation One, verified against RustyNES as an oracle.** Not a port, and it cannot be one: a MiSTer core is SystemVerilog compiled by Quartus 17.0.2 into a Cyclone V bitstream. The reference firewall therefore extends to HDL — `NES_MiSTer` and `fpganes` `rtl/` are **strict black boxes**, instantiable as opaque modules to compare *outputs*, never readable as source. **v2.5.0 is scoped to "the 6502 rung closes"** — the co-simulation harness plus a cycle-exact 6502, gated on nestest 0-diff and per-cycle bus equality — because the arithmetic does not support more: a from-scratch cycle-accurate NES core is **7–13 months FTE** against a two-to-four-week window at demonstrated cadence. PPU, APU and MiSTer integration are **v2.6–v2.9**; stating that now is better than discovering it at v2.4.6. The design is **replay, not lockstep** (the determinism contract makes a pre-recorded trace exactly the trace a lockstep run would produce, and `Nes` has no per-cycle step to lockstep *with*), **no DPI-C** (it would put `` `ifdef SIMULATION `` guards into RTL that must also pass Quartus — the exact construct that lets a simulated netlist drift from the synthesised one), and **hash first, capture on divergence** (a 4200-frame AccuracyCoin run is ~7.5 GB of per-cycle CSV; 4096-cycle hash checkpoints are 244 KB). **Two risks are accepted in writing:** the core may be **declined as a duplicate** — `NES_MiSTer` already scores 121/125 on AccuracyCoin, and *real Famicom AV hardware also scores ~121/125*, so there is no published accuracy headroom; and **the oracle can be wrong**, since 141/141 is not "matches silicon", so every rung is labelled by whether it has an **independent** oracle. Retro Remake is a planned fallback home, not a contingency. See ADR 0037, `docs/mister.md`, and [`plans/v2.5.0-fabric-plan.md`](plans/v2.5.0-fabric-plan.md).
 - **Historical detail — v2.2.4** (2026-07-24) — a **libretro / RetroArch distribution** cut whose purpose is that the RustyNES core **builds and installs cleanly through the Libretro buildbot** (<https://git.libretro.com/libretro/RustyNES>) for in-RetroArch use. **Zero emulation-core changes** — the deterministic `#![no_std]` chip stack, save-state / TAS / netplay formats, and every golden vector are byte-identical to v2.2.3, so **AccuracyCoin holds 141/141 (100.00%)**, nestest 0-diff, by construction. The work is a libretro-completeness audit + metadata correction: the core is confirmed to inherit every v2.2.3 change automatically (the fast-dot-path default, the `PPU_SNAPSHOT_VERSION` 8 / APU v4 save-state schema handled transparently by the dynamic `snapshot_core_into` sizing, the `Mapper::mix_audio` i32 widening, the Zapper model, and the `mNNN_` mapper rename), and both buildbot cross-ABIs the GitHub gate models — `x86_64-pc-windows-gnu` and `aarch64-linux-android` — build clean. `rustynes_libretro.info` (the metadata RetroArch's core downloader reads) is corrected: **`disk_control` `false` → `true`** (the FDS multi-side Disk Control interface has been wired since the buildbot recipe landed, but was advertised as absent — the real fix), `display_version` `v1.0.0` → `v2.2.4`, and the mapper count `168` → `172`. Also: the reviewer-tooling standardization onto the shared Antigravity template rides along (`scripts/agy-review.sh` + workflow). Documented libretro follow-up: **core options** (region / overscan / palette / accuracy toggles) remain unexposed (`core_options = "false"` is accurate, not stale) — a deliberate future enhancement, not a v2.2.4 gap. See `docs/STATUS.md` (single source of truth) + `CHANGELOG.md` `[2.2.4]` + `docs/libretro/`.