diff --git a/lib/providers/app_provider.dart b/lib/providers/app_provider.dart
index ff376be..1bbd0f6 100644
--- a/lib/providers/app_provider.dart
+++ b/lib/providers/app_provider.dart
@@ -10,8 +10,10 @@ import 'voice_provider.dart';
 import 'image_provider.dart' as ip;
 import '../services/tile_cache_service.dart';
 import '../services/location_tracking_service.dart';
+import '../services/packet_capture_storage_service.dart';
 import '../models/contact.dart';
 import '../models/message.dart';
+import '../models/ble_packet_log.dart';
 import '../utils/drawing_message_parser.dart';
 import '../utils/voice_message_parser.dart';
 import '../utils/image_message_parser.dart';
@@ -28,6 +30,8 @@ class AppProvider with ChangeNotifier {
   final TileCacheService tileCacheService;
   final LocationTrackingService locationTrackingService =
       LocationTrackingService();
+  final PacketCaptureStorageService packetCaptureStorageService =
+      PacketCaptureStorageService();
 
   bool _isInitialized = false;
   bool get isInitialized => _isInitialized;
@@ -52,6 +56,9 @@ class AppProvider with ChangeNotifier {
   final Map<String, String> _voiceSessionSenderKey6 = {};
   final Map<String, Timer> _voiceMissingRetryTimers = {};
   final Map<String, int> _voiceMissingRetryAttempts = {};
+  Timer? _packetCaptureFlushTimer;
+  String? _lastPersistedPacketSignature;
+  bool _isPersistingPacketCapture = false;
 
   AppProvider({
     required this.connectionProvider,
@@ -72,10 +79,67 @@ class AppProvider with ChangeNotifier {
     _loadVoiceBandPassFilterEnabled();
     _loadVoiceCompressorEnabled();
     _loadVoiceLimiterEnabled();
+    _startPacketCapturePersistence();
     _syncDrawingsOnStartup(); // Sync drawings immediately after providers load
     _isInitialized = true;
   }
 
+  void _startPacketCapturePersistence() {
+    _packetCaptureFlushTimer?.cancel();
+    _packetCaptureFlushTimer = Timer.periodic(const Duration(seconds: 2), (_) {
+      unawaited(_flushPacketCaptureLogs());
+    });
+    unawaited(_flushPacketCaptureLogs());
+  }
+
+  String _packetLogSignature(BlePacketLog log) {
+    final prefix = log.rawData.length <= 12
+        ? log.rawData
+        : log.rawData.sublist(0, 12);
+    final prefixHex = prefix.map((b) => b.toRadixString(16).padLeft(2, '0')).join();
+    return '${log.timestamp.microsecondsSinceEpoch}|'
+        '${log.direction.name}|${log.responseCode ?? -1}|'
+        '${log.rawData.length}|$prefixHex';
+  }
+
+  Future<void> _flushPacketCaptureLogs() async {
+    if (_isPersistingPacketCapture) return;
+    _isPersistingPacketCapture = true;
+    try {
+      final logs = connectionProvider.bleService.packetLogs;
+      if (logs.isEmpty) return;
+
+      List<BlePacketLog> toPersist = const [];
+      if (_lastPersistedPacketSignature == null) {
+        toPersist = logs;
+      } else {
+        final lastSig = _lastPersistedPacketSignature!;
+        var lastIndex = -1;
+        for (var i = logs.length - 1; i >= 0; i--) {
+          if (_packetLogSignature(logs[i]) == lastSig) {
+            lastIndex = i;
+            break;
+          }
+        }
+        if (lastIndex == -1) {
+          // In-memory log rotated or cleared; persist current window to avoid gaps.
+          toPersist = logs;
+        } else if (lastIndex < logs.length - 1) {
+          toPersist = logs.sublist(lastIndex + 1);
+        }
+      }
+
+      if (toPersist.isNotEmpty) {
+        await packetCaptureStorageService.appendLogs(toPersist);
+      }
+      _lastPersistedPacketSignature = _packetLogSignature(logs.last);
+    } catch (e) {
+      debugPrint('❌ [AppProvider] Packet capture flush failed: $e');
+    } finally {
+      _isPersistingPacketCapture = false;
+    }
+  }
+
   /// Sync drawings from messages on app startup (before BLE connection)
   Future<void> _syncDrawingsOnStartup() async {
     // Wait for MessagesProvider to finish initializing
@@ -1243,6 +1307,8 @@ class AppProvider with ChangeNotifier {
 
   @override
   void dispose() {
+    _packetCaptureFlushTimer?.cancel();
+    unawaited(_flushPacketCaptureLogs());
     // Remove connection state listener
     connectionProvider.removeListener(_handleConnectionStateChange);
     // Clear location service callbacks
diff --git a/lib/services/packet_capture_storage_service.dart b/lib/services/packet_capture_storage_service.dart
new file mode 100644
index 0000000..dd7a68a
--- /dev/null
+++ b/lib/services/packet_capture_storage_service.dart
@@ -0,0 +1,146 @@
+import 'dart:convert';
+import 'dart:io';
+import 'package:flutter/foundation.dart';
+import 'package:path_provider/path_provider.dart';
+import '../models/ble_packet_log.dart';
+
+class StoredPacketCapture {
+  final DateTime timestamp;
+  final String direction;
+  final int? responseCode;
+  final String? description;
+  final String rawBase64;
+  final int rawSize;
+  final double? snrDb;
+  final int? rssiDbm;
+
+  const StoredPacketCapture({
+    required this.timestamp,
+    required this.direction,
+    required this.responseCode,
+    required this.description,
+    required this.rawBase64,
+    required this.rawSize,
+    required this.snrDb,
+    required this.rssiDbm,
+  });
+
+  Map<String, dynamic> toJson() {
+    return {
+      'ts': timestamp.millisecondsSinceEpoch,
+      'dir': direction,
+      'code': responseCode,
+      'desc': description,
+      'raw': rawBase64,
+      'size': rawSize,
+      'snr': snrDb,
+      'rssi': rssiDbm,
+    };
+  }
+
+  static StoredPacketCapture fromJson(Map<String, dynamic> json) {
+    return StoredPacketCapture(
+      timestamp: DateTime.fromMillisecondsSinceEpoch((json['ts'] as num).toInt()),
+      direction: (json['dir'] as String?) ?? 'rx',
+      responseCode: (json['code'] as num?)?.toInt(),
+      description: json['desc'] as String?,
+      rawBase64: (json['raw'] as String?) ?? '',
+      rawSize: (json['size'] as num?)?.toInt() ?? 0,
+      snrDb: (json['snr'] as num?)?.toDouble(),
+      rssiDbm: (json['rssi'] as num?)?.toInt(),
+    );
+  }
+}
+
+/// Durable storage for raw BLE packets so future features can consume
+/// historical packet bytes across app restarts.
+class PacketCaptureStorageService {
+  static const String _fileName = 'packet_captures.jsonl';
+  static const int _maxStoredPackets = 20000;
+
+  File? _file;
+
+  Future<File> _resolveFile() async {
+    if (_file != null) return _file!;
+    final dir = await getApplicationSupportDirectory();
+    final file = File('${dir.path}/$_fileName');
+    if (!await file.exists()) {
+      await file.create(recursive: true);
+    }
+    _file = file;
+    return file;
+  }
+
+  Future<void> appendLogs(List<BlePacketLog> logs) async {
+    if (logs.isEmpty) return;
+    try {
+      final file = await _resolveFile();
+      final sink = file.openWrite(mode: FileMode.append);
+      for (final log in logs) {
+        final row = StoredPacketCapture(
+          timestamp: log.timestamp,
+          direction: log.direction.name,
+          responseCode: log.responseCode,
+          description: log.description,
+          rawBase64: base64Encode(log.rawData),
+          rawSize: log.rawData.length,
+          snrDb: log.logRxDataInfo?.snrDb,
+          rssiDbm: log.logRxDataInfo?.rssiDbm,
+        );
+        sink.writeln(jsonEncode(row.toJson()));
+      }
+      await sink.flush();
+      await sink.close();
+      await _pruneIfNeeded(file);
+    } catch (e) {
+      debugPrint('❌ [PacketCaptureStorage] Failed to append logs: $e');
+    }
+  }
+
+  Future<List<StoredPacketCapture>> loadRecent({int limit = 500}) async {
+    try {
+      final file = await _resolveFile();
+      if (!await file.exists()) return const [];
+      final lines = await file.readAsLines();
+      if (lines.isEmpty) return const [];
+      final start = lines.length > limit ? lines.length - limit : 0;
+      return lines
+          .sublist(start)
+          .where((l) => l.trim().isNotEmpty)
+          .map((l) => StoredPacketCapture.fromJson(jsonDecode(l) as Map<String, dynamic>))
+          .toList();
+    } catch (e) {
+      debugPrint('❌ [PacketCaptureStorage] Failed to load recent logs: $e');
+      return const [];
+    }
+  }
+
+  Future<int> count() async {
+    try {
+      final file = await _resolveFile();
+      if (!await file.exists()) return 0;
+      final lines = await file.readAsLines();
+      return lines.where((l) => l.trim().isNotEmpty).length;
+    } catch (_) {
+      return 0;
+    }
+  }
+
+  Future<void> clear() async {
+    try {
+      final file = await _resolveFile();
+      if (await file.exists()) {
+        await file.writeAsString('');
+      }
+    } catch (e) {
+      debugPrint('❌ [PacketCaptureStorage] Failed to clear logs: $e');
+    }
+  }
+
+  Future<void> _pruneIfNeeded(File file) async {
+    final lines = await file.readAsLines();
+    if (lines.length <= _maxStoredPackets) return;
+    final keep = lines.sublist(lines.length - _maxStoredPackets);
+    await file.writeAsString('${keep.join('\n')}\n');
+  }
+}
diff --git a/lib/widgets/messages/message_bubble.dart b/lib/widgets/messages/message_bubble.dart
index 8a627b8..0287978 100644
--- a/lib/widgets/messages/message_bubble.dart
+++ b/lib/widgets/messages/message_bubble.dart
@@ -551,16 +551,43 @@ class _MessageBubbleState extends State<MessageBubble> {
       ToastLogger.success(context, l10n.textCopiedToClipboard);
     }
 
-    showDialog(
+    showModalBottomSheet(
       context: context,
-      builder: (context) => AlertDialog(
-        title: Text(l10n.messageTechnicalDetails),
-        content: SizedBox(
-          width: double.maxFinite,
-          child: SingleChildScrollView(
-            child: Column(
-              crossAxisAlignment: CrossAxisAlignment.stretch,
-              children: [
+      isScrollControlled: true,
+      backgroundColor: Theme.of(context).colorScheme.surface,
+      shape: const RoundedRectangleBorder(
+        borderRadius: BorderRadius.vertical(top: Radius.circular(16)),
+      ),
+      builder: (sheetContext) => SafeArea(
+        child: SizedBox(
+          height: MediaQuery.of(sheetContext).size.height * 0.85,
+          child: Column(
+            crossAxisAlignment: CrossAxisAlignment.stretch,
+            children: [
+              Padding(
+                padding: const EdgeInsets.fromLTRB(16, 14, 8, 8),
+                child: Row(
+                  children: [
+                    Expanded(
+                      child: Text(
+                        l10n.messageTechnicalDetails,
+                        style: Theme.of(sheetContext).textTheme.titleLarge,
+                      ),
+                    ),
+                    IconButton(
+                      onPressed: () => Navigator.pop(sheetContext),
+                      icon: const Icon(Icons.close),
+                      tooltip: l10n.close,
+                    ),
+                  ],
+                ),
+              ),
+              Expanded(
+                child: SingleChildScrollView(
+                  padding: const EdgeInsets.symmetric(horizontal: 16),
+                  child: Column(
+                    crossAxisAlignment: CrossAxisAlignment.stretch,
+                    children: [
                 Wrap(
                   spacing: 8,
                   runSpacing: 8,
@@ -839,16 +866,13 @@ class _MessageBubbleState extends State<MessageBubble> {
                     ),
                   ],
                 ),
-              ],
-            ),
+                    ],
+                  ),
+                ),
+              ),
+            ],
           ),
         ),
-        actions: [
-          TextButton(
-            onPressed: () => Navigator.pop(context),
-            child: Text(AppLocalizations.of(context)!.close),
-          ),
-        ],
       ),
     );
   }