diff --git a/lib/features/device/services/device_message.dart b/lib/features/device/services/device_message.dart
index a1115c4..fa82e58 100644
--- a/lib/features/device/services/device_message.dart
+++ b/lib/features/device/services/device_message.dart
@@ -1,5 +1,7 @@
 import 'dart:convert';
 
+import 'package:uuid/uuid.dart';
+
 /// 下位机消息类型
 ///
 /// 对应《下位机交互数据模型.md》中定义的四种 type 字段。
@@ -147,18 +149,11 @@ class DeviceMessage {
 
 /// 消息 ID 生成器
 ///
-/// 使用时间戳 + 随机数生成全局唯一 ID（避免引入 uuid 依赖）。
-/// 格式：`<millis>-<rand>`，例如 `1717500000000-1a2b3c`
+/// 基于 [Uuid.v4] 生成全局唯一 ID（128 位随机，标准 36 字符 hex-with-dashes 形式）。
+/// 例如 `550e8400-e29b-41d4-a716-446655440000`。
 class MessageIdGenerator {
-  int _counter = 0;
+  static const Uuid _uuid = Uuid();
 
   /// 生成下一个唯一 ID
-  String next() {
-    _counter = (_counter + 1) & 0xFFFFFF;
-    final ts = DateTime.now().millisecondsSinceEpoch.toRadixString(36);
-    final rand = (_counter.toRadixString(36) +
-            (DateTime.now().microsecondsSinceEpoch & 0xFFFF).toRadixString(36))
-        .padLeft(4, '0');
-    return '$ts-$rand';
-  }
+  String next() => _uuid.v4();
 }
diff --git a/lib/features/device/services/json_protocol.dart b/lib/features/device/services/json_protocol.dart
index a2f2bd9..3bffa7d 100644
--- a/lib/features/device/services/json_protocol.dart
+++ b/lib/features/device/services/json_protocol.dart
@@ -1,6 +1,7 @@
 import 'dart:convert';
 import 'dart:typed_data';
 
+import 'device_log.dart';
 import 'device_message.dart';
 
 /// JSON 协议层帧编解码器
@@ -67,7 +68,7 @@ class JsonProtocolService {
         (_buffer[2] << 8) |
         _buffer[3];
     if (len <= 0 || len > _maxFrameBytes) {
-      // 长度异常，丢弃首字节重新对齐
+      DeviceLog.warn('tryDecode: 异常长度=$len 丢弃首字节 0x${_buffer[0].toRadixString(16).padLeft(2, '0')}');
       _buffer.removeAt(0);
       return (null, 0);
     }
diff --git a/pubspec.lock b/pubspec.lock
index 5e89e28..b3ac7eb 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -763,7 +763,7 @@ packages:
     source: hosted
     version: "0.5.2"
   uuid:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: uuid
       sha256: "1fef9e8e11e2991bb773070d4656b7bd5d850967a2456cfc83cf47925ba79489"
diff --git a/pubspec.yaml b/pubspec.yaml
index 1bfb76f..24575a8 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -43,6 +43,9 @@ dependencies:
   # USB 串口通信（Android USB Host 模式下的 CH340/FTDI/CP210x/PL2303 等芯片）
   usb_serial: ^0.5.0
 
+  # 串口消息 ID 生成（UUID v4）
+  uuid: ^4.5.1
+
 dev_dependencies:
   flutter_test:
     sdk: flutter