diff --git a/android/app/src/main/kotlin/io/openim/flutter/openim/MainActivity.kt b/android/app/src/main/kotlin/io/openim/flutter/openim/MainActivity.kt
index 089a7f3..6b5230d 100644
--- a/android/app/src/main/kotlin/io/openim/flutter/openim/MainActivity.kt
+++ b/android/app/src/main/kotlin/io/openim/flutter/openim/MainActivity.kt
@@ -31,10 +31,10 @@ class MainActivity : FlutterActivity() {
     private val WEBVIEW_CACHE_CHANNEL = "io.openim.flutter.im_webview_app/webview_cache"
     private val TAG = "MainActivity"
     private val MAX_BRANDING_ICON_SIZE = 192
-    private val WEBVIEW_DATA_DIRECTORY_SUFFIX = "h5_shell_fresh_profile_v4"
+    private val WEBVIEW_DATA_DIRECTORY_SUFFIX = "h5_shell_fresh_profile_v5"
     private val WEBVIEW_STORAGE_RESET_PREFS = "h5_shell_webview_storage"
     private val WEBVIEW_STORAGE_RESET_KEY = "reset_version"
-    private val WEBVIEW_STORAGE_RESET_VERSION = 4
+    private val WEBVIEW_STORAGE_RESET_VERSION = 5
 
     override fun onCreate(savedInstanceState: android.os.Bundle?) {
         configureWebViewDataDirectory()
diff --git a/lib/config/app_config.dart b/lib/config/app_config.dart
index 8d831a4..0502675 100644
--- a/lib/config/app_config.dart
+++ b/lib/config/app_config.dart
@@ -21,7 +21,11 @@ class AppConfig {
     final host = environmentHosts.isNotEmpty
         ? environmentHosts.first
         : 'h5-im.imharry.work';
-    return _normalizeHomeUrl(host);
+    final uri = Uri.parse(_normalizeHomeUrl(host));
+    final queryParameters = Map<String, String>.from(uri.queryParameters)
+      ..['_h5_t'] = DateTime.now().millisecondsSinceEpoch.toString();
+
+    return uri.replace(queryParameters: queryParameters).toString();
   }
 
   static String withFreshShellParams(String url) {
diff --git a/lib/main.dart b/lib/main.dart
index 070b24b..1fb3ea5 100644
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -11,8 +11,48 @@ import 'config/app_config.dart';
 const _shellBackground = Color(0xFFF8FBFF);
 const _shellAccent = Color(0xFF0089FF);
 const _shellSubText = Color(0xFF8E9AB0);
+const _showH5DebugOverlay = bool.fromEnvironment(
+  'H5_SHELL_DEBUG',
+  defaultValue: true,
+);
 const _shellBrandingChannel =
     MethodChannel('io.openim.flutter.im_webview_app/shell_branding');
+const _h5MountedCheckScript = r'''
+(() => document.body?.classList.contains('app-mounted') === true)();
+''';
+const _h5SnapshotScript = r'''
+(() => {
+  const shrinkAssetUrl = (value) => {
+    try {
+      const absolute = new URL(value, window.location.href).href;
+      const match = absolute.match(/\/assets\/[^?#]+/);
+      return match ? match[0] : absolute;
+    } catch (_) {
+      return value || '';
+    }
+  };
+
+  const scripts = Array.from(document.scripts)
+    .map((script) => script.src)
+    .filter(Boolean)
+    .map(shrinkAssetUrl)
+    .filter((src) => src.includes('/assets/'));
+  const bodyText = (document.body?.innerText || '')
+    .replace(/\s+/g, ' ')
+    .slice(0, 180);
+  let shellBrand = '';
+  try {
+    shellBrand = window.sessionStorage.getItem('OPENIM_FLUTTER_SHELL_BRAND') || '';
+  } catch (_) {}
+
+  return JSON.stringify({
+    href: window.location.href,
+    scripts,
+    bodyText,
+    shellBrand,
+  });
+})();
+''';
 
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
@@ -97,6 +137,7 @@ class _H5ShellPageState extends State<H5ShellPage> {
 
   int _progress = 0;
   String? _loadError;
+  String _h5DebugText = 'H5 loading...';
   bool _showShellCover = true;
   bool _shellBrandingLoaded = false;
   late ShellBranding _shellBranding;
@@ -161,7 +202,9 @@ class _H5ShellPageState extends State<H5ShellPage> {
 
   Future<void> _handlePageFinished() async {
     await _loadShellBrandingIfNeeded();
+    await _waitForH5Mounted();
     await _syncShellBranding();
+    await _updateH5DebugSnapshot();
     if (mounted) {
       setState(() {
         _progress = 100;
@@ -204,6 +247,58 @@ class _H5ShellPageState extends State<H5ShellPage> {
     return _runJavaScriptSafely(script);
   }
 
+  Future<void> _waitForH5Mounted() async {
+    for (var index = 0; index < 20; index += 1) {
+      try {
+        final result = await _controller.runJavaScriptReturningResult(
+          _h5MountedCheckScript,
+        );
+        if (result == true || result.toString() == 'true') {
+          return;
+        }
+      } catch (_) {}
+      await Future<void>.delayed(const Duration(milliseconds: 100));
+    }
+  }
+
+  Future<void> _updateH5DebugSnapshot() async {
+    if (!_showH5DebugOverlay) {
+      return;
+    }
+
+    try {
+      final result = await _controller.runJavaScriptReturningResult(
+        _h5SnapshotScript,
+      );
+      final snapshot = _decodeJavaScriptStringResult(result);
+      debugPrint('[H5Shell] snapshot: $snapshot');
+      if (mounted) {
+        setState(() => _h5DebugText = snapshot);
+      }
+    } catch (error) {
+      debugPrint('[H5Shell] snapshot failed: $error');
+      if (mounted) {
+        setState(() => _h5DebugText = 'H5 snapshot failed: $error');
+      }
+    }
+  }
+
+  String _decodeJavaScriptStringResult(Object? result) {
+    if (result == null) {
+      return '';
+    }
+    if (result is String) {
+      try {
+        final decoded = jsonDecode(result);
+        if (decoded is String) {
+          return decoded;
+        }
+      } catch (_) {}
+      return result;
+    }
+    return result.toString();
+  }
+
   Future<void> _loadHome() async {
     await _loadUrl(_freshHomeUrl());
   }
@@ -290,6 +385,15 @@ class _H5ShellPageState extends State<H5ShellPage> {
                   message: _loadError!,
                   onRetry: () => unawaited(_loadHome()),
                 ),
+              if (_showH5DebugOverlay)
+                Positioned(
+                  left: 8,
+                  right: 8,
+                  bottom: 10,
+                  child: IgnorePointer(
+                    child: _H5DebugOverlay(text: _h5DebugText),
+                  ),
+                ),
             ],
           ),
         ),
@@ -339,6 +443,36 @@ class _ErrorPanel extends StatelessWidget {
   }
 }
 
+class _H5DebugOverlay extends StatelessWidget {
+  const _H5DebugOverlay({required this.text});
+
+  final String text;
+
+  @override
+  Widget build(BuildContext context) {
+    return DecoratedBox(
+      decoration: BoxDecoration(
+        color: Colors.black.withValues(alpha: 0.72),
+        borderRadius: BorderRadius.circular(6),
+      ),
+      child: Padding(
+        padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 6),
+        child: Text(
+          text,
+          maxLines: 5,
+          overflow: TextOverflow.ellipsis,
+          style: const TextStyle(
+            color: Colors.white,
+            fontSize: 10,
+            height: 1.25,
+            letterSpacing: 0,
+          ),
+        ),
+      ),
+    );
+  }
+}
+
 class _ShellFallback extends StatelessWidget {
   const _ShellFallback();