diff --git a/src/gos/gos_keil.h b/src/gos/gos_keil.h
index 84530d16..863986d4 100644
--- a/src/gos/gos_keil.h
+++ b/src/gos/gos_keil.h
@@ -18,9 +18,14 @@
 /*
  * Keil RTX uses the CMSIS RTOS interface. Therefore, just use the CMSIS RTOS port
  */
-#define GFX_USE_OS_KEIL FALSE		// Disable KEIL to avoid error: "GOS: More than one operation system has been defined as TRUE."
-#define GFX_USE_OS_CMSIS TRUE
 
+// Disable KEIL to avoid error: "GOS: More than one operation system has been defined as TRUE."
+#undef GFX_USE_OS_KEIL
+#define GFX_USE_OS_KEIL FALSE
+
+// Enable generic CMSIS RTOS implementation
+#undef GFX_USE_OS_CMSIS
+#define GFX_USE_OS_CMSIS TRUE
 #include "gos_cmsis.h"
 
 #endif /* GFX_USE_OS_KEIL */