fix: simplify method call for writing data in UsbSerialService

- Fix operator precedence bug in _handleAutoAddConfig where `flags &
  flag != 0` was parsed as `flags & (flag != 0)`, always checking bit 0
  instead of the correct flag bit
- Populate _contacts from cache in loadContactCache() so contacts
  persist across app restarts
- Toggle DTR low→high on USB connect to force device to see a fresh
  connection
- Add 10ms inter-frame delay for USB sends to prevent missed responses
- Deassert DTR before closing USB port on disconnect/dispose

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/connector/meshcore_connector.dart

@@ -289,6 +289,10 @@ class MeshCoreConnector extends ChangeNotifier {
     );
   }
 
+  List<Contact> get allContacts => List.unmodifiable([
+    ..._contacts,
+    ..._discoveredContacts.where((c) => !c.isActive),
+  ]);
   List<Contact> get discoveredContacts {
     return List.unmodifiable(_discoveredContacts);
   }
@@ -704,6 +708,9 @@ class MeshCoreConnector extends ChangeNotifier {
     _knownContactKeys
       ..clear()
       ..addAll(cached.map((c) => c.publicKeyHex));
+    _contacts
+      ..clear()
+      ..addAll(cached);
     for (final contact in cached) {
       _ensureContactSmazSettingLoaded(contact.publicKeyHex);
     }
@@ -1536,6 +1543,10 @@ class MeshCoreConnector extends ChangeNotifier {
 
     if (_activeTransport == MeshCoreTransportType.usb) {
       await _usbManager.write(data);
+      // Brief pause so the device firmware can process each frame before the
+      // next arrives. Without this, rapid-fire frames over USB can cause the
+      // device to miss responses (especially on reconnect).
+      await Future<void>.delayed(const Duration(milliseconds: 10));
     } else if (_activeTransport == MeshCoreTransportType.tcp) {
       await _tcpConnector.write(data);
     } else {
@@ -2909,6 +2920,8 @@ class MeshCoreConnector extends ChangeNotifier {
   void _handleContact(Uint8List frame, {bool isContact = true}) {
     final contact = Contact.fromFrame(frame);
     if (contact != null) {
+      _handleDiscovery(contact, frame, noNotify: true, addActive: true);
+
       if (contact.type == advTypeRepeater) {
         _contactUnreadCount.remove(contact.publicKeyHex);
         _unreadStore.saveContactUnreadCount(
@@ -4717,6 +4730,12 @@ class MeshCoreConnector extends ChangeNotifier {
           (_autoAddRoomServers && type == advTypeRoom) ||
           (_autoAddSensors && type == advTypeSensor)) {
         _handleContactAdvert(newContact);
+        _handleDiscovery(
+          newContact,
+          rawPacket,
+          noNotify: true,
+          addActive: true,
+        );
       } else {
         _handleDiscovery(newContact, rawPacket);
       }
@@ -4741,8 +4760,20 @@ class MeshCoreConnector extends ChangeNotifier {
 
       // CRITICAL: Preserve user's path override when contact is refreshed from device
       _contacts[existingIndex] = existing.copyWith(
-        latitude: hasLocation ? latitude : existing.latitude,
+        latitude:
-        longitude: hasLocation ? longitude : existing.longitude,
+            hasLocation &&
+                latitude != null &&
+                latitude.abs() <= 90 &&
+                (latitude != 0 || longitude != 0)
+            ? latitude
+            : existing.latitude,
+        longitude:
+            hasLocation &&
+                longitude != null &&
+                longitude.abs() <= 180 &&
+                (latitude != 0 || longitude != 0)
+            ? longitude
+            : existing.longitude,
         name: hasName ? name : existing.name,
         path: Uint8List.fromList(path.reversed.toList()),
         pathLength: path.length,
@@ -4813,11 +4844,11 @@ class MeshCoreConnector extends ChangeNotifier {
     try {
       reader.skipBytes(1); // Skip the response code byte
       final flags = reader.readByte();
-      _autoAddUsers = flags & autoAddChatFlag != 0;
+      _autoAddUsers = (flags & autoAddChatFlag) != 0;
-      _autoAddRepeaters = flags & autoAddRepeaterFlag != 0;
+      _autoAddRepeaters = (flags & autoAddRepeaterFlag) != 0;
-      _autoAddRoomServers = flags & autoAddRoomServerFlag != 0;
+      _autoAddRoomServers = (flags & autoAddRoomServerFlag) != 0;
-      _autoAddSensors = flags & autoAddSensorFlag != 0;
+      _autoAddSensors = (flags & autoAddSensorFlag) != 0;
-      _overwriteOldest = flags & autoAddOverwriteOldestFlag != 0;
+      _overwriteOldest = (flags & autoAddOverwriteOldestFlag) != 0;
     } catch (e) {
       appLogger.error('Failed to parse auto-add config: $e', tag: 'Connector');
     }
@@ -4827,6 +4858,7 @@ class MeshCoreConnector extends ChangeNotifier {
     Contact contact,
     Uint8List rawPacket, {
     bool noNotify = false,
+    bool addActive = false,
   }) {
     appLogger.info('Discovered new contact: ${contact.name}', tag: 'Connector');
 
@@ -4847,7 +4879,7 @@ class MeshCoreConnector extends ChangeNotifier {
             longitude: contact.longitude,
             lastSeen: contact.lastSeen,
             flags: 0,
-            isActive: false,
+            isActive: addActive,
           );
       notifyListeners();
       unawaited(_persistDiscoveredContacts());
@@ -4865,7 +4897,7 @@ class MeshCoreConnector extends ChangeNotifier {
       longitude: contact.longitude,
       lastSeen: contact.lastSeen,
       lastMessageAt: contact.lastMessageAt,
-      isActive: false,
+      isActive: addActive,
       flags: 0,
     );
     _discoveredContacts.add(disContact);

lib/connector/meshcore_connector_usb.dart

@@ -64,6 +64,8 @@ class MeshCoreUsbManager {
 
   Future<void> write(Uint8List data) => _service.write(data);
 
+  Future<void> writeRaw(Uint8List data) => _service.writeRaw(data);
+
   // --- Label management ---
   void updateConnectedLabel(String selfName) {
     _service.updateConnectedLabel(selfName);

lib/models/app_settings.dart

@@ -40,6 +40,8 @@ class AppSettings {
   final UnitSystem unitSystem;
   final Set<String> mutedChannels;
   final bool mapShowDiscoveryContacts;
+  final String tcpServerAddress;
+  final int tcpServerPort;
 
   AppSettings({
     this.clearPathOnMaxRetry = false,
@@ -68,6 +70,8 @@ class AppSettings {
     this.unitSystem = UnitSystem.metric,
     Set<String>? mutedChannels,
     this.mapShowDiscoveryContacts = true,
+    this.tcpServerAddress = '',
+    this.tcpServerPort = 0,
   }) : batteryChemistryByDeviceId = batteryChemistryByDeviceId ?? {},
        batteryChemistryByRepeaterId = batteryChemistryByRepeaterId ?? {},
        mutedChannels = mutedChannels ?? {};
@@ -100,6 +104,8 @@ class AppSettings {
       'unit_system': unitSystem.value,
       'muted_channels': mutedChannels.toList(),
       'map_show_discovery_contacts': mapShowDiscoveryContacts,
+      'tcp_server_address': tcpServerAddress,
+      'tcp_server_port': tcpServerPort,
     };
   }
 
@@ -157,6 +163,8 @@ class AppSettings {
           {},
       mapShowDiscoveryContacts:
           json['map_show_discovery_contacts'] as bool? ?? true,
+      tcpServerAddress: json['tcp_server_address'] as String? ?? '',
+      tcpServerPort: json['tcp_server_port'] as int? ?? 0,
     );
   }
 
@@ -187,6 +195,8 @@ class AppSettings {
     UnitSystem? unitSystem,
     Set<String>? mutedChannels,
     bool? mapShowDiscoveryContacts,
+    String? tcpServerAddress,
+    int? tcpServerPort,
   }) {
     return AppSettings(
       clearPathOnMaxRetry: clearPathOnMaxRetry ?? this.clearPathOnMaxRetry,
@@ -225,6 +235,8 @@ class AppSettings {
       mutedChannels: mutedChannels ?? this.mutedChannels,
       mapShowDiscoveryContacts:
           mapShowDiscoveryContacts ?? this.mapShowDiscoveryContacts,
+      tcpServerAddress: tcpServerAddress ?? this.tcpServerAddress,
+      tcpServerPort: tcpServerPort ?? this.tcpServerPort,
     );
   }
 }

lib/models/contact.dart

@@ -65,7 +65,17 @@ class Contact {
     return '$pathLength hops';
   }
 
-  bool get hasLocation => latitude != null && longitude != null;
+  bool get hasLocation {
+    const double epsilon = 1e-6;
+    final lat = latitude ?? 0.0;
+    final lon = longitude ?? 0.0;
+    return (lat.abs() > epsilon || lon.abs() > epsilon) &&
+        lat >= -90.0 &&
+        lat <= 90.0 &&
+        lon >= -180.0 &&
+        lon <= 180.0;
+  }
+
   bool get isFavorite => (flags & contactFlagFavorite) != 0;
 
   Contact copyWith({
@@ -108,7 +118,7 @@ class Contact {
   }
 
   String get pathIdList {
-    final pathBytes = _pathBytesForDisplay;
+    final pathBytes = pathBytesForDisplay;
     if (pathBytes.isEmpty) return '';
     final parts = <String>[];
     final groupSize = pathHashSize;
@@ -130,43 +140,7 @@ class Contact {
     return "<${publicKeyHex.substring(0, 8)}...${publicKeyHex.substring(publicKeyHex.length - 8)}>";
   }
 
-  Uint8List? get traceRouteBytes {
+  Uint8List get pathBytesForDisplay {
-    final pathBytes = _pathBytesForDisplay;
-    Uint8List? traceBytes;
-
-    if (pathBytes.isEmpty) {
-      traceBytes = Uint8List(1);
-      traceBytes[0] = publicKey[0];
-      return traceBytes;
-    }
-
-    if (type == advTypeRepeater || type == advTypeRoom) {
-      final len = (pathBytes.length + pathBytes.length + 1);
-      traceBytes = Uint8List(len);
-      traceBytes[pathBytes.length] = publicKey[0];
-      for (int i = 0; i < pathBytes.length; i++) {
-        traceBytes[i] = pathBytes[i];
-        if (i < pathBytes.length) {
-          traceBytes[len - 1 - i] = pathBytes[i];
-        }
-      }
-    } else {
-      if (pathBytes.length < 2) {
-        return pathBytes[0] == 0 ? null : pathBytes;
-      }
-      final len = (pathBytes.length + pathBytes.length - 1);
-      traceBytes = Uint8List(len);
-      for (int i = 0; i < pathBytes.length; i++) {
-        traceBytes[i] = pathBytes[i];
-        if (i < pathBytes.length - 1) {
-          traceBytes[len - 1 - i] = pathBytes[i];
-        }
-      }
-    }
-    return traceBytes;
-  }
-
-  Uint8List get _pathBytesForDisplay {
     if (pathOverride != null) {
       if (pathOverride! < 0) return Uint8List(0);
       return pathOverrideBytes ?? Uint8List(0);
@@ -197,6 +171,7 @@ class Contact {
       double? lat, lon;
       final latRaw = reader.readInt32LE();
       final lonRaw = reader.readInt32LE();
+
       if (latRaw != 0 || lonRaw != 0) {
         lat = latRaw / 1e6;
         lon = lonRaw / 1e6;

lib/screens/channel_message_path_screen.dart

@@ -40,10 +40,7 @@ class ChannelMessagePathScreen extends StatelessWidget {
         final primaryPath = !channelMessage && !message.isOutgoing
             ? Uint8List.fromList(primaryPathTmp.reversed.toList())
             : primaryPathTmp;
-        final contacts = <Contact>[
+        final contacts = connector.allContacts;
-          ...connector.contacts,
-          ...connector.discoveredContacts,
-        ];
         final hops = _buildPathHops(primaryPath, contacts, l10n);
         final hasHopDetails = primaryPath.isNotEmpty;
         final observedLabel = _formatObservedHops(
@@ -65,8 +62,9 @@ class ChannelMessagePathScreen extends StatelessWidget {
                     builder: (context) => PathTraceMapScreen(
                       title: context.l10n.contacts_repeaterPathTrace,
                       path: primaryPath,
-                      flipPathRound: true,
+                      flipPathAround: true,
-                      reversePathRound: !message.isOutgoing && !channelMessage,
+                      reversePathAround:
+                          !(!channelMessage && !message.isOutgoing),
                     ),
                   ),
                 ),
@@ -367,10 +365,7 @@ class _ChannelMessagePathMapScreenState
             : selectedPathTmp;
 
         final selectedIndex = _indexForPath(selectedPath, observedPaths);
-        final contacts = <Contact>[
+        final contacts = connector.allContacts;
-          ...connector.contacts,
-          ...connector.discoveredContacts,
-        ];
         final hops = _buildPathHops(selectedPath, contacts, context.l10n);
 
         final points = <LatLng>[];

lib/screens/chat_screen.dart

@@ -858,7 +858,7 @@ class _ChatScreenState extends State<ChatScreen> {
                 builder: (context) => PathTraceMapScreen(
                   title: context.l10n.contacts_repeaterPathTrace,
                   path: Uint8List.fromList(pathBytes),
-                  flipPathRound: true,
+                  flipPathAround: true,
                   targetContact: widget.contact,
                 ),
               ),
@@ -1027,7 +1027,7 @@ class _ChatScreenState extends State<ChatScreen> {
     final currentPathLabel = _currentPathLabel(currentContact);
 
     // Filter out the current contact from available contacts
-    final availableContacts = connector.contacts
+    final availableContacts = connector.allContacts
         .where((c) => c != widget.contact)
         .toList();
 

lib/screens/contacts_screen.dart

@@ -1064,7 +1064,7 @@ class _ContactsScreenState extends State<ContactsScreen>
             if (isRepeater) ...[
               ListTile(
                 leading: const Icon(Icons.radar, color: Colors.green),
-                title: contact.pathLength > 0
+                title: contact.pathBytesForDisplay.isNotEmpty
                     ? Text(context.l10n.contacts_pathTrace)
                     : Text(context.l10n.contacts_ping),
                 onTap: () {
@@ -1072,10 +1072,12 @@ class _ContactsScreenState extends State<ContactsScreen>
                     context,
                     MaterialPageRoute(
                       builder: (context) => PathTraceMapScreen(
-                        title: contact.pathLength > 0
+                        title: contact.pathBytesForDisplay.isNotEmpty
                             ? context.l10n.contacts_repeaterPathTrace
                             : context.l10n.contacts_repeaterPing,
-                        path: contact.traceRouteBytes ?? Uint8List(0),
+                        path: contact.pathBytesForDisplay,
+                        flipPathAround: true,
+                        targetContact: contact,
                       ),
                     ),
                   );
@@ -1100,10 +1102,12 @@ class _ContactsScreenState extends State<ContactsScreen>
                     context,
                     MaterialPageRoute(
                       builder: (context) => PathTraceMapScreen(
-                        title: contact.pathLength > 0
+                        title: contact.pathBytesForDisplay.isNotEmpty
                             ? context.l10n.contacts_roomPathTrace
                             : context.l10n.contacts_roomPing,
-                        path: contact.traceRouteBytes ?? Uint8List(0),
+                        path: contact.pathBytesForDisplay,
+                        flipPathAround: contact.pathBytesForDisplay.isNotEmpty,
+                        targetContact: contact,
                       ),
                     ),
                   );
@@ -1145,7 +1149,8 @@ class _ContactsScreenState extends State<ContactsScreen>
                           title: context.l10n.contacts_pathTraceTo(
                             contact.name,
                           ),
-                          path: contact.traceRouteBytes ?? Uint8List(0),
+                          path: contact.pathBytesForDisplay,
+                          flipPathAround: true,
                           targetContact: contact,
                         ),
                       ),

lib/screens/map_screen.dart

@@ -137,10 +137,7 @@ class _MapScreenState extends State<MapScreen> {
       builder: (context, connector, settingsService, pathHistory, child) {
         final tileCache = context.read<MapTileCacheService>();
         final settings = settingsService.settings;
-        final allContacts = <Contact>[
+        final allContacts = connector.allContacts;
-          ...connector.contacts,
-          ...connector.discoveredContacts.where((c) => !c.isActive),
-        ];
 
         final contacts = settings.mapShowDiscoveryContacts
             ? allContacts
@@ -179,20 +176,13 @@ class _MapScreenState extends State<MapScreen> {
 
         // Filter by location
         final contactsWithLocation = filteredByKeyPrefix.where((c) {
-          if (!c.hasLocation) {
+          return c.hasLocation;
-            return false;
-          }
-          return _checkLocationPlausibility(c.latitude!, c.longitude!);
         }).toList();
 
         // All contacts with a known location — used as anchors regardless of
         // time/key-prefix filters so that repeaters are always available.
         final allContactsWithLocation = allContacts
-            .where(
+            .where((c) => c.hasLocation)
-              (c) =>
-                  c.hasLocation &&
-                  _checkLocationPlausibility(c.latitude!, c.longitude!),
-            )
             .toList();
 
         // Compute guessed locations with caching

lib/screens/neighbors_screen.dart

@@ -124,10 +124,7 @@ class _NeighborsScreenState extends State<NeighborsScreen> {
 
   void _handleNeighborsResponse(MeshCoreConnector connector, Uint8List frame) {
     final buffer = BufferReader(frame);
-    final contacts = <Contact>[
+    final contacts = connector.allContacts;
-      ...connector.contacts,
-      ...connector.discoveredContacts,
-    ];
     try {
       final neighborCount = buffer.readUInt16LE();
       final parsedNeighbors = parseNeighborsData(buffer, buffer.readUInt16LE());

lib/screens/path_trace_map.dart

@@ -52,8 +52,8 @@ class PathTraceMapScreen extends StatefulWidget {
   final String title;
   final Uint8List path;
   final int? repeaterId;
-  final bool flipPathRound;
+  final bool flipPathAround;
-  final bool reversePathRound;
+  final bool reversePathAround;
   final Contact? targetContact;
 
   const PathTraceMapScreen({
@@ -61,8 +61,8 @@ class PathTraceMapScreen extends StatefulWidget {
     required this.title,
     required this.path,
     this.repeaterId,
-    this.flipPathRound = false,
+    this.flipPathAround = false,
-    this.reversePathRound = false,
+    this.reversePathAround = false,
     this.targetContact,
   });
 
@@ -93,6 +93,7 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
   ValueKey<String> _mapKey = const ValueKey('initial');
   double _pathDistanceMeters = 0.0;
   bool _showNodeLabels = true;
+  Contact? _targetContact;
 
   String _formatPathPrefixes(Uint8List pathBytes) {
     return pathBytes
@@ -158,21 +159,16 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
       });
     }
 
-    final Uint8List path;
+    final pathTmp = widget.reversePathAround
-
-    Uint8List pathTmp = widget.reversePathRound
         ? Uint8List.fromList(widget.path.reversed.toList())
         : widget.path;
 
-    if (widget.flipPathRound) {
+    final path = widget.flipPathAround ? buildPath(pathTmp) : pathTmp;
-      path = buildPath(pathTmp);
-    } else {
-      path = pathTmp;
-    }
 
     appLogger.info(
       'Initiating path trace with path: ${_formatPathPrefixes(path)}',
       tag: 'PathTraceMapScreen',
+      noNotify: !mounted,
     );
 
     final connector = Provider.of<MeshCoreConnector>(context, listen: false);
@@ -263,10 +259,7 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
           .toList();
 
       Map<int, Contact> pathContacts = {};
-      final contacts = <Contact>[
+      final contacts = connector.allContacts;
-        ...connector.contacts,
-        ...connector.discoveredContacts,
-      ];
       contacts.where((c) => c.type != advTypeChat).forEach((repeater) {
         for (var repeaterData in pathData) {
           if (listEquals(
@@ -312,18 +305,21 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
         // Compute endpoint position for the target contact.
         LatLng? targetPos;
         bool targetGuessed = false;
-        final target = widget.targetContact;
+        _targetContact = widget.targetContact;
-        if (target != null) {
+
-          if (target.hasLocation) {
+        if (_targetContact != null) {
-            targetPos = LatLng(target.latitude!, target.longitude!);
+          final tc = _targetContact!;
-          } else if (pathData.isNotEmpty) {
+          if (tc.hasLocation) {
+            targetPos = LatLng(tc.latitude!, tc.longitude!);
+          } else if (widget.path.length > 1) {
             // Infer from the last hop: average GPS contacts sharing that hop.
-            // For a round-trip path (flipPathRound), the target-side hop sits
+            // For a round-trip path (flipPathAround/reversePathAround), the target-side hop
-            // in the middle of the symmetric sequence; .last is the local side.
+            // sits in the middle of the symmetric sequence; .last is the local side.
-            final lastHop = (widget.flipPathRound && pathData.length > 1)
+            final lastHop = widget.reversePathAround
-                ? pathData[(pathData.length - 1) ~/ 2]
+                ? widget.path.first
-                : pathData.last;
+                : widget.path.last;
-            final peers = connector.contacts
+
+            final peers = connector.allContacts
                 .where(
                   (c) =>
                       c.hasLocation &&
@@ -339,12 +335,34 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
                   peers.map((c) => c.longitude!).reduce((a, b) => a + b) /
                   peers.length;
               const offsetDeg = 0.003;
-              final angle = (target.publicKey[1] / 255.0) * 2 * pi;
+              final angle = (tc.publicKey[1] / 255.0) * 2 * pi;
               targetPos = LatLng(
                 lat + offsetDeg * cos(angle),
                 lon + offsetDeg * sin(angle),
               );
               targetGuessed = true;
+            } else if (inferredPositions.containsKey(lastHop)) {
+              final lat = inferredPositions[lastHop]!.latitude;
+              final lon = inferredPositions[lastHop]!.longitude;
+              const offsetDeg = 0.003;
+              final angle = (tc.publicKey[1] / 255.0) * 2 * pi;
+              targetPos = LatLng(
+                lat + offsetDeg * cos(angle),
+                lon + offsetDeg * sin(angle),
+              );
+              targetGuessed = true;
+            } else {
+              // As a last resort, just place it at the same position as the last hop.
+              final contact = pathContacts[lastHop];
+              if (contact != null && contact.hasLocation) {
+                const offsetDeg = 0.003;
+                final angle = (tc.publicKey[1] / 255.0) * 2 * pi;
+                targetPos = LatLng(
+                  contact.latitude! + offsetDeg * cos(angle),
+                  contact.longitude! + offsetDeg * sin(angle),
+                );
+                targetGuessed = true;
+              }
             }
           }
         }
@@ -353,7 +371,12 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
 
         _points = <LatLng>[];
         _points.add(LatLng(connector.selfLatitude!, connector.selfLongitude!));
+        int hopLast = 0;
+        int hopLastLast = 0;
         for (final hop in _traceData!.pathData) {
+          if (hop == hopLastLast && widget.flipPathAround) {
+            break; //skip duplicate hops in round-trip paths
+          }
           final contact = _traceData!.pathContacts[hop];
           if (contact != null && contact.hasLocation) {
             _points.add(LatLng(contact.latitude!, contact.longitude!));
@@ -361,8 +384,14 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
             final inferred = inferredPositions[hop];
             if (inferred != null) _points.add(inferred);
           }
+          hopLastLast = hopLast;
+          hopLast = hop;
+        }
+        if (targetPos != null) {
+          if (_targetContact != null && _targetContact!.type == advTypeChat) {
+            _points.add(targetPos);
+          }
         }
-        if (targetPos != null) _points.add(targetPos);
         _polylines = _points.length > 1
             ? [
                 Polyline(
@@ -451,7 +480,8 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
                       ],
                     ),
                   ),
-                if (_hasData) _buildMapPathTrace(context, tileCache),
+                if (_hasData)
+                  _buildMapPathTrace(context, tileCache, _targetContact),
                 if (_points.isEmpty &&
                     !_hasData &&
                     !_isLoading &&
@@ -480,17 +510,28 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
   List<Marker> _buildHopMarkers(
     List<int> pathData, {
     required bool showLabels,
+    required Contact? target,
   }) {
     final markers = <Marker>[];
+    int hopLast = 0;
+    int hopLastLast = 0;
     for (final hop in pathData) {
       final contact = _traceData!.pathContacts[hop];
       final inferred = _inferredHopPositions[hop];
       final hasGps = contact != null && contact.hasLocation;
-      if (!hasGps && inferred == null) continue;
+      if (hop == hopLastLast && widget.flipPathAround) {
+        continue; //skip duplicate hops in round-trip paths
+      }
+      if (!hasGps && inferred == null) {
+        hopLastLast = hopLast;
+        hopLast = hop;
+        continue; //skip hops with no GPS and no inferred position
+      }
       final point = hasGps
           ? LatLng(contact.latitude!, contact.longitude!)
           : inferred!;
       final label = hop.toRadixString(16).padLeft(2, '0').toUpperCase();
+
       markers.add(
         Marker(
           point: point,
@@ -532,6 +573,8 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
           ),
         );
       }
+      hopLastLast = hopLast;
+      hopLast = hop;
     }
 
     final selfLat = context.read<MeshCoreConnector>().selfLatitude;
@@ -581,9 +624,9 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
 
     // Add target contact endpoint marker.
     final targetPos = _targetContactPosition;
-    if (targetPos != null) {
+    if (targetPos != null && target != null && target.type == advTypeChat) {
       final isGuessed = _targetContactIsGuessed;
-      final targetName = widget.targetContact?.name ?? '?';
+      final targetName = target.name;
       markers.add(
         Marker(
           point: targetPos,
@@ -719,6 +762,7 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
   Widget _buildMapPathTrace(
     BuildContext context,
     MapTileCacheService tileCache,
+    Contact? target,
   ) {
     return FlutterMap(
       key: _mapKey,
@@ -757,6 +801,7 @@ class _PathTraceMapScreenState extends State<PathTraceMapScreen> {
             markers: _buildHopMarkers(
               _traceData!.pathData,
               showLabels: _showNodeLabels,
+              target: target,
             ),
           ),
       ],

lib/screens/tcp_screen.dart

@@ -5,6 +5,7 @@ import 'package:provider/provider.dart';
 
 import '../connector/meshcore_connector.dart';
 import '../l10n/l10n.dart';
+import '../services/app_settings_service.dart';
 import '../utils/platform_info.dart';
 import '../widgets/adaptive_app_bar_title.dart';
 import 'contacts_screen.dart';
@@ -27,8 +28,14 @@ class _TcpScreenState extends State<TcpScreen> {
   @override
   void initState() {
     super.initState();
-    _hostController = TextEditingController();
+    _hostController = TextEditingController(
-    _portController = TextEditingController(text: '5000');
+      text: context.read<AppSettingsService>().settings.tcpServerAddress,
+    );
+    _portController = TextEditingController(
+      text: context.read<AppSettingsService>().settings.tcpServerPort > 0
+          ? context.read<AppSettingsService>().settings.tcpServerPort.toString()
+          : '',
+    );
     _connector = context.read<MeshCoreConnector>();
 
     _connectionListener = () {
@@ -39,6 +46,12 @@ class _TcpScreenState extends State<TcpScreen> {
       if (_connector.state == MeshCoreConnectionState.connected &&
           _connector.isTcpTransportConnected &&
           !_navigatedToContacts) {
+        context.read<AppSettingsService>().setTcpServerAddress(
+          _hostController.text,
+        );
+        context.read<AppSettingsService>().setTcpServerPort(
+          int.tryParse(_portController.text) ?? 0,
+        );
         _navigatedToContacts = true;
         Navigator.of(context).pushReplacement(
           MaterialPageRoute(builder: (_) => const ContactsScreen()),

lib/services/app_debug_log_service.dart

@@ -51,6 +51,7 @@ class AppDebugLogService extends ChangeNotifier {
     String message, {
     String tag = 'App',
     AppDebugLogLevel level = AppDebugLogLevel.info,
+    bool noNotify = false,
   }) {
     if (!_enabled && !kDebugMode) return;
     if (!_enabled) {
@@ -72,22 +73,24 @@ class AppDebugLogService extends ChangeNotifier {
       _entries.removeRange(0, _entries.length - maxEntries);
     }
 
+    if (!noNotify) {
       notifyListeners();
+    }
 
     // Also print to console for development
     debugPrint('[$tag] $message');
   }
 
-  void info(String message, {String tag = 'App'}) {
+  void info(String message, {String tag = 'App', bool noNotify = false}) {
-    log(message, tag: tag, level: AppDebugLogLevel.info);
+    log(message, tag: tag, level: AppDebugLogLevel.info, noNotify: noNotify);
   }
 
-  void warn(String message, {String tag = 'App'}) {
+  void warn(String message, {String tag = 'App', bool noNotify = false}) {
-    log(message, tag: tag, level: AppDebugLogLevel.warning);
+    log(message, tag: tag, level: AppDebugLogLevel.warning, noNotify: noNotify);
   }
 
-  void error(String message, {String tag = 'App'}) {
+  void error(String message, {String tag = 'App', bool noNotify = false}) {
-    log(message, tag: tag, level: AppDebugLogLevel.error);
+    log(message, tag: tag, level: AppDebugLogLevel.error, noNotify: noNotify);
   }
 
   void clear() {

lib/services/app_settings_service.dart

@@ -182,4 +182,12 @@ class AppSettingsService extends ChangeNotifier {
       ..remove(channelName);
     await updateSettings(_settings.copyWith(mutedChannels: updated));
   }
+
+  Future<void> setTcpServerAddress(String value) async {
+    await updateSettings(_settings.copyWith(tcpServerAddress: value));
+  }
+
+  Future<void> setTcpServerPort(int value) async {
+    await updateSettings(_settings.copyWith(tcpServerPort: value));
+  }
 }

lib/services/usb_serial_service_native.dart

@@ -189,6 +189,10 @@ class UsbSerialService {
           serial.setStopBits1();
           serial.setFlowControlNone();
           serial.setRTS(false);
+          // Toggle DTR low→high so the device sees a fresh connection even
+          // if the previous disconnect didn't cleanly signal DTR drop.
+          serial.setDTR(false);
+          await Future<void>.delayed(const Duration(milliseconds: 50));
           serial.setDTR(true);
           _serial = serial;
           // Update the normalized port name to whichever candidate succeeded.
@@ -249,6 +253,21 @@ class UsbSerialService {
     _status = UsbSerialStatus.connected;
   }
 
+  Future<void> writeRaw(Uint8List data) async {
+    if (!isConnected) {
+      throw StateError('USB serial port is not open');
+    }
+    if (_useAndroidUsbHost) {
+      try {
+        await _androidMethodChannel.invokeMethod<void>('write', {'data': data});
+      } on PlatformException catch (error) {
+        throw StateError(error.message ?? error.code);
+      }
+    } else {
+      _serial!.write(data);
+    }
+  }
+
   Future<void> write(Uint8List data) async {
     if (!isConnected) {
       throw StateError('USB serial port is not open');
@@ -300,6 +319,7 @@ class UsbSerialService {
       _serial = null;
       try {
         if (serial?.isOpen() == FlOpenStatus.open) {
+          serial?.setDTR(false);
           serial?.closePort();
         }
       } catch (_) {
@@ -350,6 +370,7 @@ class UsbSerialService {
       final serial = _serial;
       try {
         if (serial?.isOpen() == FlOpenStatus.open) {
+          serial?.setDTR(false);
           serial?.closePort(); // synchronous C call — kills the SerialThread
         }
       } catch (_) {}

lib/services/usb_serial_service_web.dart

@@ -127,6 +127,17 @@ class UsbSerialService {
     }
   }
 
+  Future<void> writeRaw(Uint8List data) async {
+    if (!isConnected || _writer == null) {
+      throw StateError('USB serial port is not open');
+    }
+    final promise = _writer!.callMethod<JSPromise<JSAny?>>(
+      'write'.toJS,
+      data.toJS,
+    );
+    await promise.toDart;
+  }
+
   Future<void> write(Uint8List data) async {
     if (!isConnected || _writer == null) {
       throw StateError('USB serial port is not open');

lib/utils/app_logger.dart

@@ -23,23 +23,23 @@ class AppLogger {
   bool get isEnabled => _enabled;
 
   /// Log an info message
-  void info(String message, {String tag = 'App'}) {
+  void info(String message, {String tag = 'App', bool noNotify = false}) {
     if (_enabled && _service != null) {
-      _service!.info(message, tag: tag);
+      _service!.info(message, tag: tag, noNotify: noNotify);
     }
   }
 
   /// Log a warning message
-  void warn(String message, {String tag = 'App'}) {
+  void warn(String message, {String tag = 'App', bool noNotify = false}) {
     if (_enabled && _service != null) {
-      _service!.warn(message, tag: tag);
+      _service!.warn(message, tag: tag, noNotify: noNotify);
     }
   }
 
   /// Log an error message
-  void error(String message, {String tag = 'App'}) {
+  void error(String message, {String tag = 'App', bool noNotify = false}) {
     if (_enabled && _service != null) {
-      _service!.error(message, tag: tag);
+      _service!.error(message, tag: tag, noNotify: noNotify);
     }
   }
 
@@ -48,9 +48,10 @@ class AppLogger {
     String message, {
     String tag = 'App',
     AppDebugLogLevel level = AppDebugLogLevel.info,
+    bool noNotify = false,
   }) {
     if (_enabled && _service != null) {
-      _service!.log(message, tag: tag, level: level);
+      _service!.log(message, tag: tag, level: level, noNotify: noNotify);
     }
   }
 }

lib/widgets/path_management_dialog.dart

@@ -78,7 +78,7 @@ class _PathManagementDialogState extends State<_PathManagementDialog> {
                 builder: (context) => PathTraceMapScreen(
                   title: context.l10n.contacts_repeaterPathTrace,
                   path: Uint8List.fromList(pathBytes),
-                  flipPathRound: true,
+                  flipPathAround: true,
                   targetContact: widget.contact,
                 ),
               ),
@@ -107,7 +107,7 @@ class _PathManagementDialogState extends State<_PathManagementDialog> {
     }
 
     final pathForInput = currentContact.pathIdList;
-    final availableContacts = connector.contacts
+    final availableContacts = connector.allContacts
         .where((c) => c.publicKeyHex != currentContact.publicKeyHex)
         .toList();
 

lib/widgets/path_selection_dialog.dart

@@ -1,5 +1,6 @@
 import 'dart:typed_data';
 import 'package:flutter/material.dart';
+import 'package:meshcore_open/connector/meshcore_protocol.dart';
 import '../l10n/l10n.dart';
 import '../models/contact.dart';
 
@@ -65,7 +66,7 @@ class _PathSelectionDialogState extends State<PathSelectionDialog> {
 
   void _filterValidContacts() {
     _validContacts = widget.availableContacts
-        .where((c) => c.type == 2 || c.type == 3)
+        .where((c) => c.type == advTypeRepeater || c.type == advTypeRoom)
         .toList();
   }
 

lib/widgets/snr_indicator.dart

@@ -157,10 +157,7 @@ class _SNRIndicatorState extends State<SNRIndicator> {
                   repeater.snr,
                   widget.connector.currentSf,
                 );
-                final allContacts = [
+                final allContacts = widget.connector.allContacts;
-                  ...widget.connector.contacts,
-                  ...widget.connector.discoveredContacts,
-                ];
                 final name = allContacts
                     .where((c) => c.publicKey.first == repeater.pubkeyFirstByte)
                     .map((c) => c.name)