diff --git a/app/src/main/java/com/xypower/mpapp/MainActivity.java b/app/src/main/java/com/xypower/mpapp/MainActivity.java
index a43fd53c..d34dec90 100644
--- a/app/src/main/java/com/xypower/mpapp/MainActivity.java
+++ b/app/src/main/java/com/xypower/mpapp/MainActivity.java
@@ -193,7 +193,8 @@ public class MainActivity extends AppCompatActivity {
 
         MicroPhotoContext.AppConfig appConfig = getAppConfig();
         if (TextUtils.isEmpty(appConfig.cmdid)) {
-            binding.cmdid.setText(MicroPhotoService.getSerialNumber());
+            appConfig.cmdid = MicroPhotoService.getSerialNumber();
+            binding.cmdid.setText(appConfig.cmdid);
         } else {
             binding.cmdid.setText(appConfig.cmdid);
         }