diff --git a/lib/services/sync/r2_upload_service.dart b/lib/services/sync/r2_upload_service.dart
index ea61753..986e095 100644
--- a/lib/services/sync/r2_upload_service.dart
+++ b/lib/services/sync/r2_upload_service.dart
@@ -29,11 +29,11 @@ class R2UploadService {
 
   Future<R2UploadResult> uploadTelemetryBundle({required String idToken, required String remoteRideId, required Uint8List zipBytes, required String sha256Hash, required String appVersion, Duration timeout = const Duration(seconds: 45)}) async {
     if (idToken.trim().isEmpty) return const R2UploadResult.authRequired('Firebase ID token is required for R2 upload.');
-    if (zipBytes.isEmpty) return const R2UploadResult.permanentFailure('Telemetry bundle is empty.');
+    if (zipBytes.isEmpty) return const R2UploadResult.permanentFailure('Telemetry bundle is empty.', statusCode: 400);
     // Prevent path traversal at the client boundary. The Worker remains the
     // authoritative verifier of SHA-256 and Firebase UID ownership.
-    if (!RegExp(r'^ride_[A-Za-z0-9_-]+$').hasMatch(remoteRideId)) return const R2UploadResult.permanentFailure('Invalid remote ride identifier.');
-    if (sha256Hash.trim().isEmpty) return const R2UploadResult.permanentFailure('Telemetry bundle SHA-256 is required.');
+    if (!RegExp(r'^ride_[A-Za-z0-9_-]+$').hasMatch(remoteRideId)) return const R2UploadResult.permanentFailure('Invalid remote ride identifier.', statusCode: 400);
+    if (sha256Hash.trim().isEmpty) return const R2UploadResult.permanentFailure('Telemetry bundle SHA-256 is required.', statusCode: 400);
 
     try {
       final response = await _client.put(Uri.parse('$_workerBaseUrl/r2/upload'), headers: {