diff --git a/cpu/msp430/msp430.c b/cpu/msp430/msp430.c
index 793defc35..1eff4e261 100644
--- a/cpu/msp430/msp430.c
+++ b/cpu/msp430/msp430.c
@@ -275,16 +275,16 @@ splhigh_(void)
 /*
  * Restore previous interrupt mask.
  */
-void
-splx_(int sr)
-{
-#ifdef __IAR_SYSTEMS_ICC__
-  __bis_SR_register(sr);
-#else
-  /* If GIE was set, restore it. */
-  asmv("bis %0, r2" : : "r" (sr));
-#endif
-}
+/* void */
+/* splx_(int sr) */
+/* { */
+/* #ifdef __IAR_SYSTEMS_ICC__ */
+/*   __bis_SR_register(sr); */
+/* #else */
+/*   /\* If GIE was set, restore it. *\/ */
+/*   asmv("bis %0, r2" : : "r" (sr)); */
+/* #endif */
+/* } */
 /*---------------------------------------------------------------------------*/
 /* this code will always start the TimerB if not already started */
 void
diff --git a/cpu/msp430/msp430def.h b/cpu/msp430/msp430def.h
index f869241c6..2738b7ed7 100644
--- a/cpu/msp430/msp430def.h
+++ b/cpu/msp430/msp430def.h
@@ -91,12 +91,12 @@ void msp430_sync_dco(void);
 void   *sbrk(int);
 
 typedef int spl_t;
-void    splx_(spl_t);
+/* void    splx_(spl_t); */
 spl_t   splhigh_(void);
 
 #define splhigh() splhigh_()
 #ifdef __IAR_SYSTEMS_ICC__
-#define splx(sr) sr = __get_SR_register()
+#define splx(sr) __bis_SR_register(sr)
 #else
 #define splx(sr) __asm__ __volatile__("bis %0, r2" : : "r" (sr))
 #endif