diff --git a/stm32-util/mcu-util.h b/stm32-util/mcu-util.h
index 846d6d6..bd994d6 100644
--- a/stm32-util/mcu-util.h
+++ b/stm32-util/mcu-util.h
@@ -9,6 +9,8 @@
 // real stm32F1 would return 0x1001 they say
 #define REAL_STM_F1_REV_CODE 0x1001
 
+#define REAL_GD_F1_REV_CODE 0x1303
+
 #define REAL_SOMETHING_F1_REV_CODE 0x2003
 
 #define ARM_REV_CODE() ((DBGMCU->IDCODE & DBGMCU_IDCODE_REV_ID_Msk) >> DBGMCU_IDCODE_REV_ID_Pos)