I restored the Web BLE behavior in [meshcore_connector.dart] to the earlier Windows/Chrome-working state aligned with the logic that was present around commit fcef3de57837983a300634aa3e0a77622e945cc2,

What is back:
- Web BLE resets handshake state before connect
- skips `requestMtu()` on web
- retries `discoverServices()` once on the transient web disconnect case
- uses the non-blocking web `setNotifyValue(true)` workaround again
- skips the immediate `SELF_INFO` wait/refresh stack on web BLE
- defers contact loading on web BLE until after channel `0`
- uses the Web-specific bounded `SELF_INFO` retry timer
- re-enables initial channel-sync gating for web BLE

lib/connector/meshcore_connector.dart

@@ -165,6 +165,7 @@ class MeshCoreConnector extends ChangeNotifier {
   bool _awaitingSelfInfo = false;
   bool _hasReceivedDeviceInfo = false;
   bool _pendingInitialChannelSync = false;
+  bool _pendingInitialContactsSync = false;
   bool _preserveContactsOnRefresh = false;
   static const int _defaultMaxContacts = 32;
   static const int _defaultMaxChannels = 8;
@@ -797,6 +798,9 @@ class MeshCoreConnector extends ChangeNotifier {
     _lastDeviceDisplayName = _deviceDisplayName;
     _manualDisconnect = false;
     _cancelReconnectTimer();
+    if (PlatformInfo.isWeb) {
+      _resetConnectionHandshakeState();
+    }
     unawaited(_backgroundService?.start());
     notifyListeners();
 
@@ -820,15 +824,37 @@ class MeshCoreConnector extends ChangeNotifier {
         rethrow;
       }
 
-      // Request larger MTU for sending larger frames
+      // Request larger MTU only on native platforms; web does not support it.
-      try {
+      if (!PlatformInfo.isWeb) {
-        final mtu = await device.requestMtu(185);
+        try {
-        debugPrint('MTU set to: $mtu');
+          final mtu = await device.requestMtu(185);
-      } catch (e) {
+          debugPrint('MTU set to: $mtu');
-        debugPrint('MTU request failed: $e, using default');
+        } catch (e) {
+          debugPrint('MTU request failed: $e, using default');
+        }
       }
 
-      List<BluetoothService> services = await device.discoverServices();
+      late final List<BluetoothService> services;
+      try {
+        services = await device.discoverServices();
+      } catch (error) {
+        debugPrint('[BLE Connect] service discovery failure: $error');
+        if (PlatformInfo.isWeb &&
+            error.toString().contains('GATT Server is disconnected')) {
+          debugPrint(
+            '[BLE Connect] retrying service discovery after transient web disconnect',
+          );
+          await Future<void>.delayed(const Duration(milliseconds: 300));
+          await device.connect(
+            timeout: const Duration(seconds: 15),
+            mtu: null,
+            license: License.free,
+          );
+          services = await device.discoverServices();
+        } else {
+          rethrow;
+        }
+      }
 
       BluetoothService? uartService;
       for (var service in services) {
@@ -855,18 +881,32 @@ class MeshCoreConnector extends ChangeNotifier {
         throw Exception("MeshCore characteristics not found");
       }
 
-      // Retry setNotifyValue with increasing delays
+      if (PlatformInfo.isWeb) {
-      bool notifySet = false;
+        debugPrint('Starting setNotifyValue(true)');
-      for (int attempt = 0; attempt < 3 && !notifySet; attempt++) {
+        debugPrint('Web: Calling setNotifyValue(true) without awaiting');
-        try {
+        unawaited(() async {
-          if (attempt > 0) {
+          try {
-            await Future.delayed(Duration(milliseconds: 500 * attempt));
+            await _txCharacteristic!.setNotifyValue(true);
+          } catch (error) {
+            debugPrint('[BLE Connect] notify failure (web, ignored): $error');
+            debugPrint('Web setNotifyValue error (ignoring): $error');
+          }
+        }());
+        debugPrint('setNotifyValue(true) configuration completed');
+      } else {
+        bool notifySet = false;
+        for (int attempt = 0; attempt < 3 && !notifySet; attempt++) {
+          try {
+            if (attempt > 0) {
+              await Future.delayed(Duration(milliseconds: 500 * attempt));
+            }
+            await _txCharacteristic!.setNotifyValue(true);
+            notifySet = true;
+          } catch (e) {
+            debugPrint('[BLE Connect] notify failure: $e');
+            debugPrint('setNotifyValue attempt ${attempt + 1}/3 failed: $e');
+            if (attempt == 2) rethrow;
           }
-          await _txCharacteristic!.setNotifyValue(true);
-          notifySet = true;
-        } catch (e) {
-          debugPrint('setNotifyValue attempt ${attempt + 1}/3 failed: $e');
-          if (attempt == 2) rethrow;
         }
       }
       _notifySubscription = _txCharacteristic!.onValueReceived.listen(
@@ -881,19 +921,27 @@ class MeshCoreConnector extends ChangeNotifier {
 
       await _requestDeviceInfo();
       _startBatteryPolling();
-      final gotSelfInfo = await _waitForSelfInfo(
+      if (PlatformInfo.isWeb &&
-        timeout: const Duration(seconds: 3),
+          _activeTransport == MeshCoreTransportType.bluetooth) {
-      );
+        // Chrome's Web Bluetooth stack commonly delays incoming notifications
-      if (!gotSelfInfo) {
+        // until the non-blocking notify setup settles. Avoid stacking extra
-        await refreshDeviceInfo();
+        // startup writes while that is happening.
-        await _waitForSelfInfo(timeout: const Duration(seconds: 3));
+      } else {
+        final gotSelfInfo = await _waitForSelfInfo(
+          timeout: const Duration(seconds: 3),
+        );
+        if (!gotSelfInfo) {
+          await refreshDeviceInfo();
+          await _waitForSelfInfo(timeout: const Duration(seconds: 3));
+        }
+
+        unawaited(syncTime());
       }
 
-      // Keep device clock aligned on every connection.
-      await syncTime();
-
       // Fetch channels so we can track unread counts for incoming messages
-      unawaited(getChannels());
+      if (!_shouldGateInitialChannelSync) {
+        unawaited(getChannels());
+      }
     } catch (e) {
       debugPrint("Connection error: $e");
       await disconnect(manual: false);
@@ -1012,6 +1060,7 @@ class MeshCoreConnector extends ChangeNotifier {
     _selfInfoRetryTimer = null;
     _hasReceivedDeviceInfo = false;
     _pendingInitialChannelSync = false;
+    _pendingInitialContactsSync = false;
   }
 
   bool get _shouldAutoReconnect =>
@@ -1020,7 +1069,9 @@ class MeshCoreConnector extends ChangeNotifier {
       _activeTransport == MeshCoreTransportType.bluetooth;
 
   bool get _shouldGateInitialChannelSync =>
-      _activeTransport == MeshCoreTransportType.usb;
+      _activeTransport == MeshCoreTransportType.usb ||
+      (_activeTransport == MeshCoreTransportType.bluetooth &&
+          PlatformInfo.isWeb);
 
   void _cancelReconnectTimer() {
     _reconnectTimer?.cancel();
@@ -1121,6 +1172,7 @@ class MeshCoreConnector extends ChangeNotifier {
     _awaitingSelfInfo = false;
     _hasReceivedDeviceInfo = false;
     _pendingInitialChannelSync = false;
+    _pendingInitialContactsSync = false;
     _maxContacts = _defaultMaxContacts;
     _maxChannels = _defaultMaxChannels;
     _isSyncingQueuedMessages = false;
@@ -1226,6 +1278,28 @@ class MeshCoreConnector extends ChangeNotifier {
 
   void _scheduleSelfInfoRetry() {
     _selfInfoRetryTimer?.cancel();
+    if (PlatformInfo.isWeb &&
+        _activeTransport == MeshCoreTransportType.bluetooth) {
+      var attempts = 0;
+      const maxAttempts = 3;
+      _selfInfoRetryTimer = Timer.periodic(const Duration(seconds: 10), (
+        timer,
+      ) {
+        if (!isConnected || !_awaitingSelfInfo) {
+          timer.cancel();
+          return;
+        }
+        if (_isLoadingContacts || _isSyncingChannels || _channelSyncInFlight) {
+          return;
+        }
+        attempts += 1;
+        unawaited(sendFrame(buildAppStartFrame()));
+        if (attempts >= maxAttempts) {
+          timer.cancel();
+        }
+      });
+      return;
+    }
     _selfInfoRetryTimer = Timer.periodic(const Duration(milliseconds: 3500), (
       timer,
     ) {
@@ -2009,6 +2083,12 @@ class MeshCoreConnector extends ChangeNotifier {
         _preserveContactsOnRefresh = false;
         notifyListeners();
         unawaited(_persistContacts());
+        if (PlatformInfo.isWeb &&
+            _activeTransport == MeshCoreTransportType.bluetooth &&
+            _isSyncingChannels &&
+            !_channelSyncInFlight) {
+          unawaited(_requestNextChannel());
+        }
         if (!_didInitialQueueSync || _pendingQueueSync) {
           _didInitialQueueSync = true;
           _pendingQueueSync = false;
@@ -2156,7 +2236,14 @@ class MeshCoreConnector extends ChangeNotifier {
     _selfInfoRetryTimer = null;
     notifyListeners();
 
-    getContacts();
+    // Auto-fetch contacts after getting self info. On web BLE, defer this
+    // until after channel 0 so startup writes stay serialized.
+    if (PlatformInfo.isWeb &&
+        _activeTransport == MeshCoreTransportType.bluetooth) {
+      _pendingInitialContactsSync = true;
+    } else {
+      getContacts();
+    }
     if (_shouldGateInitialChannelSync) {
       _maybeStartInitialChannelSync();
     }
@@ -3109,6 +3196,14 @@ class MeshCoreConnector extends ChangeNotifier {
 
         // Move to next channel
         _nextChannelIndexToRequest++;
+        if (PlatformInfo.isWeb &&
+            _activeTransport == MeshCoreTransportType.bluetooth &&
+            channel.index == 0 &&
+            _pendingInitialContactsSync) {
+          _pendingInitialContactsSync = false;
+          unawaited(getContacts());
+          return;
+        }
         unawaited(_requestNextChannel());
         return;
       } else {
@@ -3772,6 +3867,7 @@ class MeshCoreConnector extends ChangeNotifier {
     // They're only cleared on manual disconnect via disconnect() method
     _hasReceivedDeviceInfo = false;
     _pendingInitialChannelSync = false;
+    _pendingInitialContactsSync = false;
     _maxContacts = _defaultMaxContacts;
     _maxChannels = _defaultMaxChannels;
     _isSyncingQueuedMessages = false;