diff --git a/ui/flutter/lib/api/model/downloader_config.dart b/ui/flutter/lib/api/model/downloader_config.dart
index a1b98cc8..01c596cb 100644
--- a/ui/flutter/lib/api/model/downloader_config.dart
+++ b/ui/flutter/lib/api/model/downloader_config.dart
@@ -99,20 +99,14 @@ class ProxyConfig {
 
 @JsonSerializable()
 class ExtraConfigBt {
-  List<String> trackerSubscribeUrls;
-  List<String> subscribeTrackers;
-  bool autoUpdateTrackers;
+  List<String> trackerSubscribeUrls = [];
+  List<String> subscribeTrackers = [];
+  bool autoUpdateTrackers = true;
   DateTime? lastTrackerUpdateTime;
 
-  List<String> customTrackers;
+  List<String> customTrackers = [];
 
-  ExtraConfigBt({
-    this.trackerSubscribeUrls = const [],
-    this.subscribeTrackers = const [],
-    this.autoUpdateTrackers = true,
-    this.lastTrackerUpdateTime,
-    this.customTrackers = const [],
-  });
+  ExtraConfigBt();
 
   factory ExtraConfigBt.fromJson(Map<String, dynamic> json) =>
       _$ExtraConfigBtFromJson(json);
diff --git a/ui/flutter/lib/api/model/downloader_config.g.dart b/ui/flutter/lib/api/model/downloader_config.g.dart
index 1dcb12d2..6cd41ae6 100644
--- a/ui/flutter/lib/api/model/downloader_config.g.dart
+++ b/ui/flutter/lib/api/model/downloader_config.g.dart
@@ -90,24 +90,20 @@ Map<String, dynamic> _$ProxyConfigToJson(ProxyConfig instance) =>
     };
 
 ExtraConfigBt _$ExtraConfigBtFromJson(Map<String, dynamic> json) =>
-    ExtraConfigBt(
-      trackerSubscribeUrls: (json['trackerSubscribeUrls'] as List<dynamic>?)
-              ?.map((e) => e as String)
-              .toList() ??
-          const [],
-      subscribeTrackers: (json['subscribeTrackers'] as List<dynamic>?)
-              ?.map((e) => e as String)
-              .toList() ??
-          const [],
-      autoUpdateTrackers: json['autoUpdateTrackers'] as bool? ?? true,
-      lastTrackerUpdateTime: json['lastTrackerUpdateTime'] == null
+    ExtraConfigBt()
+      ..trackerSubscribeUrls = (json['trackerSubscribeUrls'] as List<dynamic>)
+          .map((e) => e as String)
+          .toList()
+      ..subscribeTrackers = (json['subscribeTrackers'] as List<dynamic>)
+          .map((e) => e as String)
+          .toList()
+      ..autoUpdateTrackers = json['autoUpdateTrackers'] as bool
+      ..lastTrackerUpdateTime = json['lastTrackerUpdateTime'] == null
           ? null
-          : DateTime.parse(json['lastTrackerUpdateTime'] as String),
-      customTrackers: (json['customTrackers'] as List<dynamic>?)
-              ?.map((e) => e as String)
-              .toList() ??
-          const [],
-    );
+          : DateTime.parse(json['lastTrackerUpdateTime'] as String)
+      ..customTrackers = (json['customTrackers'] as List<dynamic>)
+          .map((e) => e as String)
+          .toList();
 
 Map<String, dynamic> _$ExtraConfigBtToJson(ExtraConfigBt instance) {
   final val = <String, dynamic>{
diff --git a/ui/flutter/lib/app/modules/setting/views/setting_view.dart b/ui/flutter/lib/app/modules/setting/views/setting_view.dart
index a371443a..fc245a3b 100644
--- a/ui/flutter/lib/app/modules/setting/views/setting_view.dart
+++ b/ui/flutter/lib/app/modules/setting/views/setting_view.dart
@@ -138,9 +138,8 @@ class SettingView extends GetView<SettingController> {
         ],
       );
     });
-    final buildHttpUseServerCtime = _buildConfigItem(
-        'useServerCtime'.tr, () => httpConfig.useServerCtime.toString(),
-        (Key key) {
+    final buildHttpUseServerCtime = _buildConfigItem('useServerCtime'.tr,
+        () => httpConfig.useServerCtime ? 'on'.tr : 'off'.tr, (Key key) {
       return Container(
         alignment: Alignment.centerLeft,
         child: Switch(