diff --git a/README.md b/README.md
index 7db7112..96b7ffa 100644
--- a/README.md
+++ b/README.md
@@ -113,7 +113,8 @@ shared conformance corpus, documentation, and CI atomically.
 1. Install the iPad beta from
    [TestFlight](https://testflight.apple.com/join/yU4e8s6d), or build the
    Flutter app locally.
-2. Open [pyble.dev/flash](https://pyble.dev/flash) in desktop Chrome or Edge.
+2. Open [pyble.dev/flash](https://pyble.dev/flash) in a supported desktop
+   Chromium browser.
    The exact v0.4.2 hardware-tested beta is active. Browser installation and
    interrupted-flash recovery passed on both exact profiles; complete release
    qualification continues. Confirm the active version, your exact profile,
diff --git a/tools/web/DEPLOYMENT.md b/tools/web/DEPLOYMENT.md
index d656199..a837219 100644
--- a/tools/web/DEPLOYMENT.md
+++ b/tools/web/DEPLOYMENT.md
@@ -230,6 +230,14 @@ browser can load it without a certificate warning.
 
 ## Deploy a release
 
+The deploy helper proves that the active `pyble.dev` HTTPS configuration and
+security-header snippet are byte-identical to the repository before it builds
+or uploads a release. When either repository file changes, first copy it to a
+root-owned temporary path on the VPS, retain a dated backup of the installed
+file, install it atomically at the path in the bootstrap table, run `nginx -t`,
+reload Nginx, and verify the affected policy endpoints. Only then run the
+website deployment. A configuration mismatch fails before activation.
+
 The deploy helper refuses every `tools/web/.env*` filesystem node before it
 chooses a deployment mode, so Next cannot inject an inherited selector or
 other unreviewed build input. It also refuses a dirty source tree, freezes the
diff --git a/tools/web/deploy/nginx/10-pyble-dev-https.conf b/tools/web/deploy/nginx/10-pyble-dev-https.conf
index 26d2c92..a7e76bc 100644
--- a/tools/web/deploy/nginx/10-pyble-dev-https.conf
+++ b/tools/web/deploy/nginx/10-pyble-dev-https.conf
@@ -14,7 +14,10 @@ map $status $pyble_firmware_cache_control {
 # social cards out of caches while retaining the normal no-cache/no-transform
 # policy for the shared website 404 page.
 map $request_uri $pyble_not_found_cache_control {
-    ~^/social/pyble-beta-og-1200x630\.(?:png|svg)(?:\?|$) "no-store";
+    "/social/pyble-beta-og-1200x630.png" "no-store";
+    "/social/pyble-beta-og-1200x630.svg" "no-store";
+    ~^/social/pyble-beta-og-1200x630\.png\? "no-store";
+    ~^/social/pyble-beta-og-1200x630\.svg\? "no-store";
     ~^/firmware/ "no-store";
     default "no-cache, no-transform";
 }
diff --git a/tools/web/deploy/vps/deploy.sh b/tools/web/deploy/vps/deploy.sh
index d0e8262..46bddee 100755
--- a/tools/web/deploy/vps/deploy.sh
+++ b/tools/web/deploy/vps/deploy.sh
@@ -94,6 +94,54 @@ if [[ -n $(git -C "${repository_root}" status --porcelain --untracked-files=all
 fi
 readonly commit=$(git -C "${repository_root}" rev-parse HEAD)
 
+verify_remote_runtime_config() {
+    local source_config=$1
+    local installed_config=$2
+    local config_label=$3
+    local source_digest=
+    local installed_digest=
+
+    test ! -L "${source_config}"
+    test -f "${source_config}"
+    source_digest=$(shasum --algorithm 256 -- "${source_config}" |
+        awk '{ print $1 }')
+    if ! installed_digest=$(
+        ssh -o BatchMode=yes "${deploy_target}" bash -s -- \
+            "${installed_config}" <<'REMOTE'
+set -euo pipefail
+
+readonly installed_config=$1
+test ! -L "${installed_config}"
+test -f "${installed_config}"
+sha256sum -- "${installed_config}" | awk '{ print $1 }'
+REMOTE
+    ); then
+        printf 'Refusing deployment: active %s is missing or unsafe at %s.\n' \
+            "${config_label}" "${installed_config}" >&2
+        exit 65
+    fi
+    if [[ ! "${source_digest}" =~ ^[0-9a-f]{64}$ ||
+        ! "${installed_digest}" =~ ^[0-9a-f]{64}$ ]]; then
+        printf 'Refusing deployment: %s digest validation failed.\n' \
+            "${config_label}" >&2
+        exit 65
+    fi
+    if [[ "${source_digest}" != "${installed_digest}" ]]; then
+        printf 'Refusing deployment: active %s differs from repository source; install, validate, and reload Nginx first.\n' \
+            "${config_label}" >&2
+        exit 65
+    fi
+}
+
+verify_remote_runtime_config \
+    "${script_directory}/../nginx/10-pyble-dev-https.conf" \
+    /etc/nginx/sites-available/10-pyble-dev-https.conf \
+    'pyble.dev HTTPS configuration'
+verify_remote_runtime_config \
+    "${script_directory}/../nginx/pyble-security-headers.conf" \
+    /etc/nginx/snippets/pyble-security-headers.conf \
+    'security-header configuration'
+
 verify_firmware_tree_parity() {
     local expected_tree=$1
     local actual_tree=$2
@@ -1048,6 +1096,16 @@ rollback_on_smoke_error() {
     fi
     exit "${smoke_status}"
 }
+reject_post_activation_smoke() {
+    local smoke_status=$1
+    if [[ ! "${smoke_status}" =~ ^[1-9][0-9]*$ ||
+        "${smoke_status}" -gt 255 ]]; then
+        printf 'Invalid post-activation smoke status: %s.\n' \
+            "${smoke_status}" >&2
+        return 70
+    fi
+    return "${smoke_status}"
+}
 trap rollback_on_smoke_error ERR
 
 smoke_root=$(mktemp -d)
@@ -1122,13 +1180,13 @@ for firmware_release in out/firmware/v*; do
         if [[ "${firmware_path}" == "${checksum_line}" ]]; then
             printf 'Invalid firmware checksum entry: %s\n' \
                 "${checksum_line}" >&2
-            exit 67
+            reject_post_activation_smoke 67
         fi
         case "${firmware_path}" in
             ""|/*|*\\*|*..*)
                 printf 'Unsafe firmware checksum path: %s\n' \
                     "${firmware_path}" >&2
-                exit 67
+                reject_post_activation_smoke 67
                 ;;
         esac
         mkdir -p -- "$(dirname -- "${public_release}/${firmware_path}")"
@@ -1154,7 +1212,7 @@ readonly not_found_status=$(
 if [[ "${not_found_status}" != 404 ]]; then
     printf 'Public 404 smoke failed: expected 404, received %s.\n' \
         "${not_found_status}" >&2
-    exit 66
+    reject_post_activation_smoke 66
 fi
 
 retired_public_asset_paths=(
@@ -1180,7 +1238,7 @@ for retired_public_asset_path in "${retired_public_asset_paths[@]}"; do
                 "${retired_public_asset_method}" \
                 "${retired_public_asset_path}" \
                 "${retired_public_asset_status}" >&2
-            exit 66
+            reject_post_activation_smoke 66
         fi
         retired_public_asset_normalized_headers="${retired_public_asset_headers}.normalized"
         tr -d '\r' < "${retired_public_asset_headers}" > \
@@ -1190,7 +1248,7 @@ for retired_public_asset_path in "${retired_public_asset_paths[@]}"; do
             printf 'Retired public asset smoke failed for %s %s: Cache-Control is not no-store.\n' \
                 "${retired_public_asset_method}" \
                 "${retired_public_asset_path}" >&2
-            exit 66
+            reject_post_activation_smoke 66
         fi
     done
     retired_public_asset_index=$((retired_public_asset_index + 1))
@@ -1227,7 +1285,7 @@ for firmware_not_found_path in "${firmware_not_found_paths[@]}"; do
                 "${firmware_not_found_method}" \
                 "${firmware_not_found_path}" \
                 "${firmware_not_found_status}" >&2
-            exit 66
+            reject_post_activation_smoke 66
         fi
         firmware_not_found_normalized_headers="${firmware_not_found_headers}.normalized"
         tr -d '\r' < "${firmware_not_found_headers}" > \
@@ -1237,7 +1295,7 @@ for firmware_not_found_path in "${firmware_not_found_paths[@]}"; do
             printf 'Firmware 404 smoke failed for %s %s: Cache-Control is not no-store.\n' \
                 "${firmware_not_found_method}" \
                 "${firmware_not_found_path}" >&2
-            exit 66
+            reject_post_activation_smoke 66
         fi
     done
     firmware_not_found_index=$((firmware_not_found_index + 1))
diff --git a/tools/web/src/test/vps-deployment-contract.test.ts b/tools/web/src/test/vps-deployment-contract.test.ts
index 0188b0b..b06a0e2 100644
--- a/tools/web/src/test/vps-deployment-contract.test.ts
+++ b/tools/web/src/test/vps-deployment-contract.test.ts
@@ -89,6 +89,29 @@ describe("Cloudflare-fronted VPS deployment", () => {
     expect(headers).toContain("Strict-Transport-Security");
   });
 
+  it("refuses deployment when active Nginx contracts differ from source", async () => {
+    const script = await readFile(
+      join(deploymentRoot, "vps", "deploy.sh"),
+      "utf8",
+    );
+    const parityIndex = script.indexOf("verify_remote_runtime_config");
+    const buildIndex = script.indexOf(
+      "NEXT_TELEMETRY_DISABLED=1 npm run check",
+    );
+    const uploadIndex = script.search(/\brsync\b/);
+
+    expect(parityIndex).toBeGreaterThan(-1);
+    expect(parityIndex).toBeLessThan(buildIndex);
+    expect(parityIndex).toBeLessThan(uploadIndex);
+    expect(script).toContain(
+      "/etc/nginx/sites-available/10-pyble-dev-https.conf",
+    );
+    expect(script).toContain("/etc/nginx/snippets/pyble-security-headers.conf");
+    expect(script).toMatch(
+      /verify_remote_runtime_config\(\)[\s\S]*?shasum[\s\S]*?ssh[\s\S]*?sha256sum[\s\S]*?(?:mismatch|differs)/i,
+    );
+  });
+
   it("keeps firmware 404 responses non-cacheable through the shared error page", async () => {
     const config = await readFile(
       join(deploymentRoot, "nginx", "10-pyble-dev-https.conf"),
@@ -112,9 +135,11 @@ describe("Cloudflare-fronted VPS deployment", () => {
       readFile(join(deploymentRoot, "vps", "deploy.sh"), "utf8"),
     ]);
 
-    expect(config).toContain(
-      '~^/social/pyble-beta-og-1200x630\\.(?:png|svg)(?:\\?|$) "no-store";',
-    );
+    for (const extension of ["png", "svg"]) {
+      const path = `/social/pyble-beta-og-1200x630.${extension}`;
+      expect(config).toContain(`"${path}" "no-store";`);
+      expect(config).toContain(`~^${path.replace(".", "\\.")}\\? "no-store";`);
+    }
     expect(script).toContain("retired_public_asset_paths=(");
     expect(script).toContain("/social/pyble-beta-og-1200x630.png");
     expect(script).toContain("/social/pyble-beta-og-1200x630.svg");
@@ -257,6 +282,24 @@ describe("Cloudflare-fronted VPS deployment", () => {
       );
   });
 
+  it("routes explicit post-activation smoke rejections through rollback", async () => {
+    const script = await readFile(
+      join(deploymentRoot, "vps", "deploy.sh"),
+      "utf8",
+    );
+    const smokeStart = script.indexOf("trap rollback_on_smoke_error ERR");
+    const smokeEnd = script.indexOf("trap - ERR", smokeStart + 1);
+    const smokeRegion = script.slice(smokeStart, smokeEnd);
+
+    expect(smokeStart).toBeGreaterThan(-1);
+    expect(smokeEnd).toBeGreaterThan(smokeStart);
+    expect(script).toMatch(
+      /reject_post_activation_smoke\(\)[\s\S]*?return\s+"\$\{smoke_status\}"/,
+    );
+    expect(smokeRegion).not.toMatch(/\bexit\s+(?:66|67)\b/);
+    expect(smokeRegion).toMatch(/\breject_post_activation_smoke\s+(?:66|67)\b/);
+  });
+
   it("arms rollback before the current symlink can switch or the activation SSH can fail", async () => {
     const script = await readFile(
       join(deploymentRoot, "vps", "deploy.sh"),