diff --git a/.github/workflows/run-unit-tests.yml b/.github/workflows/run-unit-tests.yml
index 38bd1429f..817748f0c 100644
--- a/.github/workflows/run-unit-tests.yml
+++ b/.github/workflows/run-unit-tests.yml
@@ -219,6 +219,22 @@ jobs:
           python3 -B test/test_client_acl_cli.py -v
           python3 -B test/test_client_acl_response.py -v
 
+      - name: Setup Node for official app compatibility tests
+        uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+
+      - name: Cache pinned official app protocol source
+        uses: actions/cache@v4
+        with:
+          path: ~/.cache/meshcore-tests
+          key: official-app-84bc39a950735aaffa93d912556852a4c22e235d0cc4e4d04790113207f13a68
+
+      - name: Verify stock app radio and Access Control compatibility
+        run: |
+          node --version
+          python3 -B test/test_official_app_compatibility.py -v
+
       - name: Verify ESP32 USB reboot sleep grace and G3 button wake
         run: |
           python3 -B test/test_usb_host_sleep_policy.py
diff --git a/test/fixtures/official_app_compatibility/README.txt b/test/fixtures/official_app_compatibility/README.txt
new file mode 100644
index 000000000..afb5ea7e9
--- /dev/null
+++ b/test/fixtures/official_app_compatibility/README.txt
@@ -0,0 +1,55 @@
+Official app compatibility source witness
+
+Source: https://app.meshcore.nz/main.dart.js
+Observed: 2026-10-04
+Bytes: 9494192
+SHA-256: 84bc39a950735aaffa93d912556852a4c22e235d0cc4e4d04790113207f13a68
+
+Run:
+  python3 -B test/test_official_app_compatibility.py -v
+
+Requires Node.js 22 and a native C++17 compiler. Linux native fixtures run
+under AddressSanitizer and UndefinedBehaviorSanitizer. No PlatformIO or
+hardware is used. The complete web application is not copied into Git.
+
+Default external cache:
+  ~/.cache/meshcore-tests/84bc39a950735aaffa93d912556852a4c22e235d0cc4e4d04790113207f13a68/main.dart.js
+
+An optional MESHCORE_OFFICIAL_APP_BUNDLE path selects an existing external
+bundle. Its bytes and SHA must match. Without that variable, a cold cache
+downloads the public source and verifies its exact size and SHA before saving.
+CI should use actions/setup-node with node-version 22 and actions/cache for
+~/.cache/meshcore-tests, keyed by the full SHA above. The public URL is mutable:
+if it changes and no pinned cache exists, the test fails explicitly. Updating
+the source pin and function witnesses requires review; it never silently uses
+the new app or replaces its parsers with test implementations.
+
+The JS harness extracts and evaluates unmodified compiled app function bodies:
+ACL request builder/decoder, CMD50 builder, binary frame parser, SENT/Binary
+listeners, CLI response stripping, and all three radio settings screen parsers.
+It also executes the app's byte writer/reader and event emitter. Mocked
+boundaries are the Dart runtime/type helpers, timer scheduler, transport,
+widget state/localization and RNG. The app's schema/tag matching/decoders are
+not reimplemented. The deterministic RNG only makes a synthetic request
+repeatable; its random value is not the Companion's replay timestamp.
+
+The exact app-generated seven-byte ACL query is passed to the production
+repeater receive/ACL handler, with actual packet budget/admission/serialization.
+Only the crypto primitive and radio queue are mocked in that native fixture;
+zero padding reflects the production cipher block size, not crypto validation.
+The one-admin direct case asserts 11-byte plaintext, 16-byte padded ciphertext,
+20-byte payload and 22-byte zero-path wire size. All 32 decoded cases cover
+0/1/22/23/24/25/32/256 entries, direct/flood and zero/maximum return path.
+Large ACLs retain legacy one-packet truncation, not a complete list guarantee.
+Actual Companion and CommonCLI radio replies cover saved automatic/explicit
+preambles and an active temporary/secondary profile. A fifth field must invoke
+each stock app radio screen's existing error path.
+
+The host listener accepts a matching ACL reply 3s into its estimate-2s/+5s
+window. Actual firmware callback/SENT deadline behavior is separately exercised
+by test_companion_delayed_reply_delivery.py. The global uncorrelated SENT race
+is retained as an expected app-level mechanism witness. Neither this synthetic
+race nor the newer firmware deadline regression proves the cause of the user's
+intermittent Access Control timeout. The successful pre-fix live retry remains
+valid. This public web code is not proof of the installed iOS binary/version,
+and these native tests do not exercise RF, BLE fragmentation or app UI lifecycle.
diff --git a/test/fixtures/official_app_compatibility/app_contract.js b/test/fixtures/official_app_compatibility/app_contract.js
new file mode 100644
index 000000000..8a798e875
--- /dev/null
+++ b/test/fixtures/official_app_compatibility/app_contract.js
@@ -0,0 +1,207 @@
+// Execute unmodified functions extracted from the SHA-pinned official web app.
+// Only Dart runtime, scheduler, widget state and transport boundaries are mocked.
+// This is a protocol contract witness, not an iOS/BLE UI automation test.
+"use strict";
+const assert = require("assert/strict");
+const fs = require("fs");
+const vm = require("vm");
+const input = JSON.parse(fs.readFileSync(process.argv[2], "utf8"));
+const source = fs.readFileSync(input.bundle, "utf8");
+
+function extract(needle, at = 0) {
+  const begin = source.indexOf(needle, at);
+  assert(begin >= 0, `Missing pinned app function: ${needle}`);
+  const open = source.indexOf("{", begin);
+  let depth = 0, quote = null, escaped = false;
+  for (let end = open; end < source.length; ++end) {
+    const ch = source[end];
+    if (quote) {
+      if (escaped) escaped = false;
+      else if (ch === "\\") escaped = true;
+      else if (ch === quote) quote = null;
+    } else if (ch === '"' || ch === "'") quote = ch;
+    else if (ch === "{") ++depth;
+    else if (ch === "}" && --depth === 0) return source.slice(begin, end + 1);
+  }
+  throw Error(`Unclosed app function: ${needle}`);
+}
+
+let now = 0, timers = [], radioConnection;
+const errors = [];
+const type = {a: value => value, b: value => value instanceof Uint8Array,
+              h() { return this; }};
+const t = new Proxy({}, {get: () => type});
+const $ = {cT: () => new Uint8Array(0), cqf() {}, dF() {}, ay() {}, fQ() {},
+           vI: () => ({Ia: () => 0x78563412})};
+const B = {
+  e: {aN: (a, b) => a >> b, qP: (a, b) => Math.trunc(a / b)},
+  j: {c8: (a, start, end, b) => a.set(b.subarray(0, end - start), start),
+      gcc: a => a.buffer, gS: a => a[0]},
+  be: {gcc: a => a.buffer},
+  d: {bc: (a, b) => a.includes(b), iV: (a, b, c) => a.split(b).join(c)}
+};
+const J = {
+  a3: () => ({gt: a => a.length, gap: a => a.length === 0, i: (a, i) => a[i]}),
+  i2: (a, b, c) => new Uint8Array(a, b, c),
+  po: a => new Uint8Array(a), lx: (a, b, c) => new DataView(a, b, c),
+  c6: (a, b) => a.push(b), aaW: (a, predicate) => {
+    for (let i = a.length - 1; i >= 0; --i) if (predicate.$1(a[i])) a.splice(i, 1);
+  },
+  bf: a => { let i = -1; return {v: () => ++i < a.length, gM: () => a[i]}; },
+  cTH: a => a.a, kz: (a, b) => a.split(b), aA: a => a.length,
+  a1: (a, i) => a[i], p: (a, b) => a === b, cri: (a, n) => a.toFixed(n)
+};
+function deferred() {
+  const result = {a: 0};
+  result.promise = new Promise((resolve, reject) => {
+    result.resolve = resolve; result.reject = reject;
+  });
+  result.then = result.promise.then.bind(result.promise);
+  return result;
+}
+const A = {
+  k: deferred, f: fn => fn,
+  j: (fn, result) => { fn(0, null); return result.promise; },
+  e: (value, fn) => Promise.resolve(value).then(v => fn(0, v), e => fn(1, e)),
+  i: (value, result) => result.resolve(value), h: (error, result) => result.reject(error),
+  V: function() { return deferred(); },
+  am: function(value) {
+    this.a = value;
+    this.bK = (_, result) => { value.a = 30; value.resolve(result); };
+    this.bD = error => { value.a = 30; value.reject(error); };
+  },
+  a: value => value, aX: value => value,
+  ew: (start, end, length) => {
+    const result = end === null ? length : end;
+    assert(start >= 0 && result >= start && result <= length); return result;
+  },
+  en: (bytes, start, end) => ({cS: () => bytes.slice(start, end)}), cj: () => type,
+  b3: () => ({$1() {}}), b6() {},
+  bF: (_, __, ___, ms) => ({a: ms * 1000}), bT: function(a) { this.a = a; },
+  fh: (duration, callback) => timers.push({due: now + duration.a / 1000, callback}),
+  csH: callback => queueMicrotask(() => callback.$0()),
+  wc: function() {}, an: () => radioConnection,
+  kY: value => { const number = Number(value); assert(Number.isFinite(number)); return number; },
+  cS: value => { const number = Number(value); assert(Number.isInteger(number)); return number; },
+  c: () => ({glp: () => "invalid radio fields", glb: () => "radio error"}),
+  av: (...args) => errors.push(args), L: error => error,
+  aH: (_, error) => errors.push(error)
+};
+const context = vm.createContext({A, B, J, t, $, u: {AD: "tag mismatch", b1: "CLI mismatch"},
+                                 Uint8Array, DataView, ArrayBuffer, Math, Date});
+function constructor(name) {
+  const code = extract(`${name}:function ${name}(`).replace(`${name}:`, `A.${name}=`);
+  vm.runInContext(code, context);
+}
+for (const name of ["cZ", "d3", "fo", "ab7", "U1", "aba", "PS", "acs",
+                    "aSq", "aSp", "aSr", "aSs", "aSf", "pK", "b0Z", "b0Y",
+                    "b0X", "b1_", "b0W"]) constructor(name);
+for (const name of ["cZ", "d3", "fo", "aba", "aSq", "aSp", "aSr", "aSs", "aSf",
+                    "b0V", "b0Z", "b0Y", "b0X", "b1_", "b0W", "wc"]) {
+  if (!A[name]) A[name] = function() {};
+  vm.runInContext(extract(`A.${name}.prototype={`), context);
+}
+Object.assign(A, vm.runInContext(`({${extract("eD(a){")},${extract("d_f(a){")},${extract("bO(a,b){")}})`, context));
+
+function connection() {
+  const connection = new A.wc();
+  const map = new Map();
+  connection.a = {
+    cu(_, key, factory) { if (!map.has(key)) map.set(key, factory.$0()); },
+    i: (_, key) => map.get(key), Z: (_, key) => map.has(key),
+    ey: (_, fn) => { for (const [key, value] of map) fn.$2(key, value); }
+  };
+  for (const name of ["eY", "N", "bCk", "bu", "dT", "W7"])
+    connection[name] = A.b0V.prototype[name];
+  connection.writes = [];
+  connection.d6 = async bytes => { connection.writes.push(Buffer.from(bytes)); };
+  return connection;
+}
+async function settle() { for (let i = 0; i < 20; ++i) await Promise.resolve(); }
+async function advance(ms) {
+  now += ms;
+  for (const timer of timers.filter(timer => timer.due <= now)) timer.callback.$0();
+  timers = timers.filter(timer => timer.due > now); await settle();
+}
+function sent(tag, estimate = 2000) {
+  const bytes = Buffer.alloc(10); bytes[0] = 6;
+  bytes.writeUInt32LE(tag, 2); bytes.writeUInt32LE(estimate, 6); return bytes;
+}
+function binary(tag, hex) {
+  const prefix = Buffer.alloc(6); prefix[0] = 140; prefix.writeUInt32LE(tag, 2);
+  return Buffer.concat([prefix, Buffer.from(hex, "hex")]);
+}
+const key = Uint8Array.from({length: 32}, (_, i) => i + 1);
+
+async function main() {
+  const builder = connection();
+  const pending = builder.aQ1(key); pending.catch(() => {}); await settle();
+  assert.equal(builder.writes.length, 1);
+  assert.equal(builder.writes[0].length, 40);
+  assert.equal(builder.writes[0][0], 50);
+  assert.equal(builder.writes[0].subarray(1, 33).toString("hex"), Buffer.from(key).toString("hex"));
+  assert.equal(builder.writes[0].subarray(33).toString("hex"), "05000012345678");
+  if (input.mode === "build") {
+    console.log(JSON.stringify({command: builder.writes[0].toString("hex"),
+                               request: builder.writes[0].subarray(33).toString("hex")}));
+    return;
+  }
+  let decoded = 0;
+  for (const reply of input.acl) {
+    const client = connection(); const promise = client.aQ1(key); await settle();
+    client.aL9(sent(51)); await settle();
+    const timer = timers[timers.length - 1]; assert.equal(timer.due - now, 7000);
+    // Valid matching ACL data remains accepted past the old 2400ms deadline.
+    await advance(3000); client.aL9(binary(51, reply.body)); await settle();
+    const result = await promise;
+    assert.equal(result.a.length, reply.entries);
+    for (let index = 0; index < result.a.length; ++index) {
+      const entry = result.a[index]; assert.equal(entry.b.a, 3);
+      assert.equal(Buffer.from(entry.a).toString("hex"), reply.body.slice(index * 14, index * 14 + 12));
+    }
+    ++decoded;
+  }
+  // Retain the stock app's global SENT-listener race as an explicit witness.
+  // This demonstrates a mechanism and does not identify an observed iOS cause.
+  const raced = connection(); let failure;
+  const request = raced.aQ1(key).catch(error => { failure = error; }); await settle();
+  raced.aL9(sent(50)); await settle(); raced.aL9(sent(51)); await settle();
+  raced.aL9(binary(51, input.acl.find(reply => reply.entries === 1).body)); await settle();
+  await advance(7000); await request; assert.equal(failure, "timeout");
+
+  // Feed actual firmware CLI output through the stock response stripping
+  // callback, then through every stock radio screen's unmodified HH parser.
+  let screens = 0;
+  const radioNeedle = 'return A.e(A.an().d5(m.a.c,"get radio"),$async$HH)';
+  let at = 0;
+  while ((at = source.indexOf(radioNeedle, at)) >= 0) {
+    const begin = source.lastIndexOf("\nHH(){", at) + 1;
+    assert(begin > 0); const code = extract("HH(){", begin);
+    const method = vm.runInContext(`({${code}}).HH`, context);
+    for (const name of code.matchAll(/new A\.(\w+)\(m\)/g)) constructor(name[1]);
+    for (const radio of input.radio) {
+      const state = {y: false, a: {c: key}, c: {}, m() {}};
+      const values = [];
+      for (const field of ["CW", "ax", "ay"])
+        state[field] = {sav: (_, value) => values.push(value)};
+      const completion = deferred(); const completer = new A.am(completion);
+      const listener = new A.aSf({a: null, b: null, c: null}, {N() {}}, key.slice(0, 6), "ab", completer);
+      listener.$1({a: key.slice(0, 6), e: `ab|${radio}`});
+      radioConnection = {d5: async () => completion.promise};
+      errors.length = 0; await method.call(state);
+      assert.deepEqual(values, ["909.500"]); assert.equal(errors.length, 0);
+      const fields = code.match(/m\.(\w+)=i\nm\.(\w+)=h\nm\.(\w+)=g/);
+      assert(fields); assert.equal(state[fields[1]], 62.5);
+      assert.equal(state[fields[2]], 7); assert.equal(state[fields[3]], 5);
+    }
+    // The exact previously broken fifth field must reach the app's error path.
+    const state = {y: false, a: {c: key}, c: {}, m() {}};
+    radioConnection = {d5: async () => "909.5,62.5,7,5,48"};
+    errors.length = 0; await method.call(state); assert.equal(errors.length, 1);
+    ++screens; at += radioNeedle.length;
+  }
+  assert.equal(screens, 3);
+  console.log(JSON.stringify({acl_cases: decoded, radio_screens: screens,
+                             stock_sent_race_witness: true, actual_ios_cause_proven: false}));
+}
+main().catch(error => { console.error(error); process.exitCode = 1; });
diff --git a/test/test_client_acl_response.py b/test/test_client_acl_response.py
index 0b0f34791..473a2ebe8 100644
--- a/test/test_client_acl_response.py
+++ b/test/test_client_acl_response.py
@@ -28,36 +28,41 @@ def parse_acl(buf):
     return res
 
 
+def production_acl_methods():
+    source = (ROOT / "examples/simple_repeater/MyMesh.cpp").read_text()
+    handler = extract_braced(source, "int MyMesh::handleRequest(")
+    prefix = handler[:handler.index("  if (payload[0] == REQ_TYPE_GET_STATUS)")]
+    acl = extract_braced(handler, "if (payload[0] == REQ_TYPE_GET_ACCESS_LIST)")
+    generated = prefix + acl + "\nreturn 0;\n}\n"
+    receive = extract_braced(source, "if (type == PAYLOAD_TYPE_REQ) { // request")
+    generated += """
+    void MyMesh::receive(mesh::Packet* packet, uint8_t* data, size_t len) {
+      ClientInfo* client = &sender;
+      const uint8_t type = PAYLOAD_TYPE_REQ;
+      uint8_t secret[PUB_KEY_SIZE] = {};
+    """ + receive + "\n}\n"
+    mesh_source = (ROOT / "src/Mesh.cpp").read_text()
+    generated += "namespace mesh {\n"
+    generated += "#define MAX_COMBINED_PATH (MAX_PACKET_PAYLOAD - 2 - CIPHER_BLOCK_SIZE)\n"
+    for signature in (
+        "Packet* Mesh::createPathReturn(const Identity& dest,",
+        "Packet* Mesh::createPathReturn(const uint8_t* dest_hash,",
+        "Packet* Mesh::createDatagram(",
+    ):
+        generated += extract_braced(mesh_source, signature) + "\n"
+    packet_source = (ROOT / "src/Packet.cpp").read_text()
+    for signature in ("Packet::Packet()", "bool Packet::isValidPathLen("):
+        generated += extract_braced(packet_source, signature) + "\n"
+    generated += "}\n"
+    return generated
+
+
 class ClientAclResponseTest(unittest.TestCase):
     def test_production_acl_route_admission_and_replay(self):
         compiler = shutil.which("g++") or shutil.which("clang++")
         if compiler is None:
             self.skipTest("a host C++17 compiler is required")
-        source = (ROOT / "examples/simple_repeater/MyMesh.cpp").read_text()
-        handler = extract_braced(source, "int MyMesh::handleRequest(")
-        prefix = handler[:handler.index("  if (payload[0] == REQ_TYPE_GET_STATUS)")]
-        acl = extract_braced(handler, "if (payload[0] == REQ_TYPE_GET_ACCESS_LIST)")
-        generated = prefix + acl + "\nreturn 0;\n}\n"
-        receive = extract_braced(source, "if (type == PAYLOAD_TYPE_REQ) { // request")
-        generated += """
-void MyMesh::receive(mesh::Packet* packet, uint8_t* data, size_t len) {
-  ClientInfo* client = &sender;
-  const uint8_t type = PAYLOAD_TYPE_REQ;
-  uint8_t secret[PUB_KEY_SIZE] = {};
-""" + receive + "\n}\n"
-        mesh_source = (ROOT / "src/Mesh.cpp").read_text()
-        generated += "namespace mesh {\n"
-        generated += "#define MAX_COMBINED_PATH (MAX_PACKET_PAYLOAD - 2 - CIPHER_BLOCK_SIZE)\n"
-        for signature in (
-            "Packet* Mesh::createPathReturn(const Identity& dest,",
-            "Packet* Mesh::createPathReturn(const uint8_t* dest_hash,",
-            "Packet* Mesh::createDatagram(",
-        ):
-            generated += extract_braced(mesh_source, signature) + "\n"
-        packet_source = (ROOT / "src/Packet.cpp").read_text()
-        for signature in ("Packet::Packet()", "bool Packet::isValidPathLen("):
-            generated += extract_braced(packet_source, signature) + "\n"
-        generated += "}\n"
+        generated = production_acl_methods()
         with tempfile.TemporaryDirectory(prefix=".tmp-acl-response-", dir=ROOT) as directory:
             work = Path(directory)
             (work / "production.inc").write_text(generated, encoding="ascii")
diff --git a/test/test_companion_primary_radio_persistence.py b/test/test_companion_primary_radio_persistence.py
index 809668eb1..9ae779a51 100644
--- a/test/test_companion_primary_radio_persistence.py
+++ b/test/test_companion_primary_radio_persistence.py
@@ -186,46 +186,51 @@ int main() {
 '''
 
 
+def production_primary_radio_harness():
+    companion = (ROOT/'examples/companion_radio/MyMesh.cpp').read_text(encoding='utf-8')
+    header = (ROOT/'examples/companion_radio/MyMesh.h').read_text(encoding='utf-8')
+    infra = (ROOT/'src/helpers/CommonCLI.cpp').read_text(encoding='utf-8')
+    datastore = (ROOT/'examples/companion_radio/DataStore.cpp').read_text(encoding='utf-8')
+    handler = extract_braced(companion, 'bool MyMesh::handleCommand(')
+    # Keep the complete preprocessing sequence through the shared primary
+    # tuple validation. Only unrelated dispatch routes are omitted.
+    dispatch = handler[:handler.index('  if (sender_timestamp == 0 && handleDirectCommand')]
+    dispatch += extract_braced(handler, 'if (isCompanionRadioPrefsCommand(command))')
+    dispatch += '\nreturn false;\n}'
+
+    def boot_checks(source, member):
+        nonfinite = re.search(r'if \(!isfinite\(' + re.escape(member) + r'\)\)[^;]+;', source)
+        clamp = re.search(re.escape(member) + r' = constrain\([^;]+;', source)
+        assert nonfinite is not None
+        assert clamp is not None
+        return nonfinite.group() + '\n' + clamp.group()
+
+    support = PREFERENCES_HARNESS[:PREFERENCES_HARNESS.index('int main(')]
+    support = support.replace('@METHODS@', esp_recovery_helpers(datastore) + '\n'.join(extract_braced(datastore, sig) for sig in (
+        'bool DataStore::loadPrefs(', 'bool DataStore::loadPrefsInt(', 'bool DataStore::savePrefs(')))
+    replacements = {
+        '@SAVE_PREFS@': extract_braced(header, 'bool savePrefs()'),
+        '@COMMAND_FILTER@': extract_braced(companion, 'static bool isCompanionRadioPrefsCommand('),
+        '@DISPATCH@': dispatch,
+        '@COMPANION_SANITIZE@': boot_checks(companion, '_prefs.airtime_factor'),
+        '@INFRA_SANITIZE@': boot_checks(infra, '_prefs->airtime_factor'),
+        '@INFRA_SETTER@': extract_braced(infra, 'if (memcmp(config, "dutycycle ", 10) == 0)'),
+        '@INFRA_RADIO@': extract_braced(infra, 'if (configKeyEquals(config, "radio"))').split('{', 1)[1].rsplit('}', 1)[0],
+    }
+    harness = support + HARNESS
+    for marker, value in replacements.items():
+        harness = harness.replace(marker, value)
+    # Saving an unrelated field must not resurrect a failed tuple later.
+    harness = harness.replace('static bool error(', '''static bool saveUnrelated(MyMesh& m) {
+      m._prefs.ble_pin=654321;return m.savePrefs();
+    }
+    static bool error(''')
+    return harness
+
+
 class CompanionPrimaryRadioPersistenceTests(unittest.TestCase):
     def test_production_validation_rollback_and_dutycycle_boot(self):
-        companion = (ROOT/'examples/companion_radio/MyMesh.cpp').read_text(encoding='utf-8')
-        header = (ROOT/'examples/companion_radio/MyMesh.h').read_text(encoding='utf-8')
-        infra = (ROOT/'src/helpers/CommonCLI.cpp').read_text(encoding='utf-8')
-        datastore = (ROOT/'examples/companion_radio/DataStore.cpp').read_text(encoding='utf-8')
-        handler = extract_braced(companion, 'bool MyMesh::handleCommand(')
-        # Keep the complete preprocessing sequence through the shared primary
-        # tuple validation. Only unrelated dispatch routes are omitted.
-        dispatch = handler[:handler.index('  if (sender_timestamp == 0 && handleDirectCommand')]
-        dispatch += extract_braced(handler, 'if (isCompanionRadioPrefsCommand(command))')
-        dispatch += '\nreturn false;\n}'
-
-        def boot_checks(source, member):
-            nonfinite = re.search(r'if \(!isfinite\(' + re.escape(member) + r'\)\)[^;]+;', source)
-            clamp = re.search(re.escape(member) + r' = constrain\([^;]+;', source)
-            self.assertIsNotNone(nonfinite)
-            self.assertIsNotNone(clamp)
-            return nonfinite.group() + '\n' + clamp.group()
-
-        support = PREFERENCES_HARNESS[:PREFERENCES_HARNESS.index('int main(')]
-        support = support.replace('@METHODS@', esp_recovery_helpers(datastore) + '\n'.join(extract_braced(datastore, sig) for sig in (
-            'bool DataStore::loadPrefs(', 'bool DataStore::loadPrefsInt(', 'bool DataStore::savePrefs(')))
-        replacements = {
-            '@SAVE_PREFS@': extract_braced(header, 'bool savePrefs()'),
-            '@COMMAND_FILTER@': extract_braced(companion, 'static bool isCompanionRadioPrefsCommand('),
-            '@DISPATCH@': dispatch,
-            '@COMPANION_SANITIZE@': boot_checks(companion, '_prefs.airtime_factor'),
-            '@INFRA_SANITIZE@': boot_checks(infra, '_prefs->airtime_factor'),
-            '@INFRA_SETTER@': extract_braced(infra, 'if (memcmp(config, "dutycycle ", 10) == 0)'),
-            '@INFRA_RADIO@': extract_braced(infra, 'if (configKeyEquals(config, "radio"))').split('{', 1)[1].rsplit('}', 1)[0],
-        }
-        harness = support + HARNESS
-        for marker, value in replacements.items():
-            harness = harness.replace(marker, value)
-        # Saving an unrelated field must not resurrect a failed tuple later.
-        harness = harness.replace('static bool error(', '''static bool saveUnrelated(MyMesh& m) {
-  m._prefs.ble_pin=654321;return m.savePrefs();
-}
-static bool error(''')
+        harness = production_primary_radio_harness()
         compiler = shutil.which('g++') or shutil.which('clang++')
         self.assertIsNotNone(compiler)
         with tempfile.TemporaryDirectory(prefix='companion-primary-radio-') as directory:
diff --git a/test/test_official_app_compatibility.py b/test/test_official_app_compatibility.py
new file mode 100644
index 000000000..263a6cf86
--- /dev/null
+++ b/test/test_official_app_compatibility.py
@@ -0,0 +1,191 @@
+#!/usr/bin/env python3
+"""Execute pinned stock app code against actual firmware ACL/radio outputs.
+
+The public web build is the source witness, not proof of the installed iOS app.
+The whole app remains outside Git. A changed upstream bundle fails its SHA gate;
+an explicit source-pin update is required, never silent parser replacement.
+No PlatformIO, devices, app fork, settings writes or real radio are involved.
+"""
+
+from pathlib import Path
+import hashlib
+import json
+import os
+import shutil
+import subprocess
+import sys
+import tempfile
+import unittest
+import urllib.request
+
+from test_client_acl_response import production_acl_methods
+from test_companion_primary_radio_persistence import production_primary_radio_harness
+from test_replay_reset_integration import extract_braced
+
+ROOT = Path(__file__).resolve().parents[1]
+APP_URL = "https://app.meshcore.nz/main.dart.js"
+APP_SHA256 = "84bc39a950735aaffa93d912556852a4c22e235d0cc4e4d04790113207f13a68"
+APP_BYTES = 9494192
+JS = ROOT / "test/fixtures/official_app_compatibility/app_contract.js"
+SANITIZERS = (["-fsanitize=address,undefined", "-fno-sanitize-recover=all",
+               "-fno-pie", "-no-pie"] if sys.platform.startswith("linux") else [])
+
+
+def official_app_bundle():
+    explicit = os.environ.get("MESHCORE_OFFICIAL_APP_BUNDLE")
+    path = Path(explicit) if explicit else (
+        Path.home() / ".cache/meshcore-tests" / APP_SHA256 / "main.dart.js")
+    if not path.exists():
+        if explicit:
+            raise AssertionError(f"Missing explicit official app bundle: {path}")
+        with urllib.request.urlopen(APP_URL, timeout=45) as response:
+            data = response.read(APP_BYTES + 1)
+        if len(data) != APP_BYTES or hashlib.sha256(data).hexdigest() != APP_SHA256:
+            raise AssertionError("Official app changed: obtain the pinned cached build or review/update its source pin")
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_bytes(data)
+    data = path.read_bytes()
+    if len(data) != APP_BYTES or hashlib.sha256(data).hexdigest() != APP_SHA256:
+        raise AssertionError(f"Official app source SHA/size mismatch: {path}")
+    return path.resolve()
+
+
+def checked(command, timeout=60):
+    result = subprocess.run(command, capture_output=True, text=True, timeout=timeout)
+    if result.returncode:
+        raise AssertionError(result.stdout + result.stderr)
+    return result.stdout
+
+
+def acl_outputs(work, compiler, app_request):
+    source = production_acl_methods()
+    packet = (ROOT / "src/Packet.cpp").read_text()
+    source += "namespace mesh {\n" + "\n".join(extract_braced(packet, signature) for signature in (
+        "size_t Packet::writePath(", "int Packet::getRawLength() const",
+        "uint8_t Packet::writeTo(uint8_t dest[]) const")) + "\n}\n"
+    (work / "production.inc").write_text(source, encoding="ascii")
+    fixture = (ROOT / "test/fixtures/client_acl_response/test_client_acl_response.cpp").read_text()
+    fixture = fixture[:fixture.index("int main()")]
+    request = ",".join(str(byte) for byte in bytes.fromhex(app_request))
+    fixture += r'''
+int main() {
+  uint8_t app_query[] = {APP_QUERY};
+  static_assert(sizeof(app_query) == 7, "Exact stock app ACL request schema");
+  for (bool flood : {false, true}) for (uint8_t path_len : {0, 0x60})
+      for (unsigned clients : {0, 1, 22, 23, 24, 25, 32, 256}) {
+    MyMesh target; fill(target.acl, clients);
+    target.sender.last_timestamp = 50;
+    mesh::Packet request; request.header = flood ? ROUTE_TYPE_FLOOD : ROUTE_TYPE_DIRECT;
+    request.path_len = path_len;
+    uint8_t plaintext[11]; uint32_t tag = 51;
+    memcpy(plaintext, &tag, 4); memcpy(plaintext + 4, app_query, sizeof(app_query));
+    uint8_t secret[PUB_KEY_SIZE] = {};
+    auto* transmitted = target.createDatagram(PAYLOAD_TYPE_REQ, target.sender.id,
+                                             secret, plaintext, sizeof(plaintext));
+    // Radio send boundaries set the route bits after packet construction.
+    assert(transmitted != nullptr); transmitted->header |= ROUTE_TYPE_DIRECT;
+    assert(transmitted && transmitted->payload_len == 20 && transmitted->getRawLength() == 22);
+    target.receive(&request, plaintext, sizeof(plaintext));
+    assert(target.queued == 1 && target.sender.last_timestamp == tag);
+    auto* reply = target.last_reply; assert(reply != nullptr);
+    reply->header |= flood ? ROUTE_TYPE_FLOOD : ROUTE_TYPE_DIRECT;
+    const unsigned capacity = mesh::clientACLReplyCapacity(flood, path_len);
+    const unsigned entries = std::min(clients, (capacity - 4) / 7);
+    const unsigned route_bytes = (path_len & 63) * ((path_len >> 6) + 1);
+    const size_t body_offset = 2 * PATH_HASH_SIZE + CIPHER_MAC_SIZE + 4
+        + (flood ? 2 + route_bytes : 0);
+    if (!flood && clients == 1) {
+      assert(sizeof(plaintext) == 11 && reply->payload_len == 20 && reply->getRawLength() == 22);
+      uint8_t wire[MAX_PACKET_PAYLOAD + MAX_PATH_SIZE + 6];
+      assert(reply->writeTo(wire) == 22); // 11 plaintext -> 16 cipher -> 20 payload -> 22 wire.
+    }
+    print_legacy(reply->payload + body_offset, entries, reply->payload_len - body_offset);
+  }
+}
+'''.replace("APP_QUERY", request)
+    (work / "acl.cpp").write_text(fixture, encoding="ascii")
+    binary = work / "acl.exe"
+    checked([compiler, "-std=c++17", "-Wall", "-Wextra", "-Werror",
+             "-Wno-unused-parameter", "-Wno-unused-function", *SANITIZERS,
+             f"-I{work}", f"-I{ROOT / 'src'}", str(work / "acl.cpp"), "-o", str(binary)])
+    output = checked([str(binary)], timeout=20)
+    records = []
+    for line in output.splitlines():
+        if line.startswith("LEGACY:"):
+            _, entries, body = line.split(":")
+            records.append({"entries": int(entries), "body": body})
+    if len(records) != 32:
+        raise AssertionError(output)
+    return records
+
+
+def radio_outputs(work, compiler):
+    harness = production_primary_radio_harness()
+    # Execute the same production Companion dispatch, shared preferences parser
+    # and CommonCLI infrastructure branch with automatic/explicit preambles.
+    begin = harness.index("int main()")
+    harness = harness[:begin] + r'''
+int main() {
+  for (uint32_t timestamp : {0U, 1700000000U}) for (uint16_t preamble : {0U, 48U}) {
+    MyMesh node; assert(node._radio_profiles.savePrimaryPreamble(preamble));
+    node.radio.p.primary_temporary = true;
+    node.radio.p.primary.freq = 915; node.radio.p.primary.preamble = 96;
+    node.radio.p.secondary.params = {916, 125, 64, 8, 6};
+    node.radio.p.secondary.mode = mesh::RadioProfileMode::RxTx;
+    printf("RADIO:%s\n", node.command("get radio", timestamp));
+    Infrastructure repeater; char reply[160] = {};
+    repeater.radioCommand(reply); printf("RADIO:%s\n", reply);
+  }
+}
+'''
+    utils = (ROOT / "test/mocks/Utils.h").read_text().replace("class Utils {\npublic:", """class Utils {
+public:
+ static void printHex(Stream&,const uint8_t*,size_t){assert(false);}
+ static void fromHex(uint8_t*,size_t,const char*){assert(false);}
+""")
+    (work / "Utils.h").write_text("#include <Arduino.h>\n#include <cassert>\n" + utils, encoding="ascii")
+    (work / "Identity.h").write_text((ROOT / "test/mocks/Identity.h").read_text(), encoding="ascii")
+    transaction = (ROOT / "src/helpers/ContactFileTransaction.h").read_text()
+    (work / "ContactFileTransaction.h").write_text(transaction.replace(
+        '#include "IdentityStore.h"', '#include <helpers/IdentityStore.h>'), encoding="ascii")
+    (work / "radio.cpp").write_text(harness, encoding="ascii")
+    binary = work / "radio.exe"
+    checked([compiler, "-std=c++17", "-Wall", "-Wextra", "-Wno-unused-function",
+             "-Wno-unused-parameter", "-Wno-sign-compare", "-Wno-reorder",
+             "-DESP32_PLATFORM=1", *SANITIZERS,
+             f"-I{work}", f"-I{ROOT / 'test/fixtures/radio_profiles/mocks'}",
+             f"-I{ROOT / 'test/mocks'}", f"-I{ROOT / 'src'}", f"-I{ROOT / 'src/helpers'}", f"-I{ROOT}",
+             str(work / "radio.cpp"), *[str(ROOT / "src/helpers" / name) for name in (
+                 "ConfigSerializer.cpp", "DynamicConfigSerializer.cpp", "CommonRadioPrefs.cpp",
+                 "TxtDataHelpers.cpp", "RadioProfileCLI.cpp")], "-o", str(binary)])
+    output = checked([str(binary)], timeout=20)
+    replies = [line.removeprefix("RADIO:") for line in output.splitlines() if line.startswith("RADIO:")]
+    if len(replies) != 8:
+        raise AssertionError(output)
+    return replies
+
+
+class OfficialAppCompatibilityTests(unittest.TestCase):
+    def test_pinned_app_functions_with_production_request_and_outputs(self):
+        compiler = shutil.which("g++") or shutil.which("clang++")
+        node = shutil.which("node")
+        self.assertIsNotNone(compiler, "native C++ compiler required")
+        self.assertIsNotNone(node, "Node.js required for actual stock app functions")
+        bundle = official_app_bundle()
+        with tempfile.TemporaryDirectory(prefix="meshcore-official-app-") as directory:
+            work = Path(directory)
+            config = work / "input.json"
+            config.write_text(json.dumps({"bundle": str(bundle), "mode": "build"}), encoding="ascii")
+            generated = json.loads(checked([node, str(JS), str(config)], timeout=20))
+            config.write_text(json.dumps({"bundle": str(bundle), "mode": "check",
+                "acl": acl_outputs(work, compiler, generated["request"]),
+                "radio": radio_outputs(work, compiler)}), encoding="ascii")
+            result = json.loads(checked([node, str(JS), str(config)], timeout=20))
+            self.assertEqual(result["acl_cases"], 32)
+            self.assertEqual(result["radio_screens"], 3)
+            self.assertTrue(result["stock_sent_race_witness"])
+            self.assertFalse(result["actual_ios_cause_proven"])
+
+
+if __name__ == "__main__":
+    unittest.main()