diff --git a/app/HGProductionTool/dialog_inputserialnum.cpp b/app/HGProductionTool/dialog_inputserialnum.cpp
index 74c9498..3bd36db 100644
--- a/app/HGProductionTool/dialog_inputserialnum.cpp
+++ b/app/HGProductionTool/dialog_inputserialnum.cpp
@@ -206,7 +206,7 @@ int Dialog_InputSerialNum::getSpeedMode()
     QString devType = m_devType;
     if (getDeviceFwVersion().mid(3, 1) == "Z"); //306
     {
-        devType == "G306";
+        devType = "G306";
     }
 
     if ((int)speedMode >= 30)