diff --git a/platform/mbed_debug.h b/platform/mbed_debug.h
index 392286a15e..761c1eb99f 100644
--- a/platform/mbed_debug.h
+++ b/platform/mbed_debug.h
@@ -18,49 +18,49 @@
  */
 #ifndef MBED_DEBUG_H
 #define MBED_DEBUG_H
-#include "device.h"
+#if DEVICE_STDIO_MESSAGES
+#include <stdio.h>
+#include <stdarg.h>
+#endif
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#if DEVICE_STDIO_MESSAGES
-#include <stdio.h>
-#include <stdarg.h>
 
 /** Output a debug message
  *
  * @param format printf-style format string, followed by variables
  */
 static inline void debug(const char *format, ...) {
+#if DEVICE_STDIO_MESSAGES && !defined(NDEBUG)
     va_list args;
     va_start(args, format);
     vfprintf(stderr, format, args);
     va_end(args);
+#endif
 }
 
+
 /** Conditionally output a debug message
  *
- * NOTE: If the condition is constant false (!= 1) and the compiler optimization
+ * NOTE: If the condition is constant false (== 0) and the compiler optimization
  * level is greater than 0, then the whole function will be compiled away.
  *
- * @param condition output only if condition is true (== 1)
+ * @param condition output only if condition is true (!= 0)
  * @param format printf-style format string, followed by variables
  */
 static inline void debug_if(int condition, const char *format, ...) {
-    if (condition == 1) {
+#if DEVICE_STDIO_MESSAGES && !defined(NDEBUG)
+    if (condition) {
         va_list args;
         va_start(args, format);
         vfprintf(stderr, format, args);
         va_end(args);
     }
+#endif
 }
 
-#else
-static inline void debug(const char *format, ...) {}
-static inline void debug_if(int condition, const char *format, ...) {}
-
-#endif
 
 #ifdef __cplusplus
 }
diff --git a/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c b/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c
index e23e3e54a1..206e6813c5 100755
--- a/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c
+++ b/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c
@@ -33,6 +33,7 @@
  *---------------------------------------------------------------------------*/
 
 #include "cmsis_os.h"
+#include "mbed_error.h"
 
 
 /*----------------------------------------------------------------------------
@@ -244,7 +245,6 @@ void os_idle_demon (void) {
 /*----------------------------------------------------------------------------
  *      RTX Errors
  *---------------------------------------------------------------------------*/
-extern void error(const char* format, ...);
 extern osThreadId svcThreadGetId (void);
 
 void os_error (uint32_t err_code) {