diff --git a/ports/ARMCM3-STM32F103/stm32_serial.h b/ports/ARMCM3-STM32F103/stm32_serial.h
index ffacd00b6..421cf00fe 100644
--- a/ports/ARMCM3-STM32F103/stm32_serial.h
+++ b/ports/ARMCM3-STM32F103/stm32_serial.h
@@ -31,13 +31,13 @@
  * Tricks required to make the TRUE/FALSE declaration inside the library
  * compatible.
  */
-//#ifndef __STM32F10x_MAP_H
-//#undef FALSE
-//#undef TRUE
-//#include "stm32f10x_map.h"
-//#define FALSE 0
-//#define TRUE (!FALSE)
-//#endif
+#ifndef __STM32F10x_H
+#undef FALSE
+#undef TRUE
+#include <stm32f10x.h>
+#define FALSE 0
+#define TRUE (!FALSE)
+#endif
 
 /**
  * @brief Serial buffers size.
diff --git a/ports/ARMCM3/core_cm3.c b/ports/ARMCM3/cmsis/core_cm3.c
similarity index 100%
rename from ports/ARMCM3/core_cm3.c
rename to ports/ARMCM3/cmsis/core_cm3.c
diff --git a/ports/ARMCM3/core_cm3.h b/ports/ARMCM3/cmsis/core_cm3.h
similarity index 100%
rename from ports/ARMCM3/core_cm3.h
rename to ports/ARMCM3/cmsis/core_cm3.h