diff --git a/platform/mb851/contiki-conf.h b/platform/mb851/contiki-conf.h
index 37c2cc8f9..67e02cfb0 100644
--- a/platform/mb851/contiki-conf.h
+++ b/platform/mb851/contiki-conf.h
@@ -182,7 +182,7 @@ typedef unsigned long clock_time_t;
 
 #define CLOCK_CONF_SECOND 1000
 
-typedef unsigned long long rtimer_clock_t;
+typedef unsigned long rtimer_clock_t;
 #define RTIMER_CLOCK_LT(a,b)     ((signed short)((a)-(b)) < 0)
 
 /* LEDs ports MB851 */
diff --git a/platform/mbxxx/contiki-conf.h b/platform/mbxxx/contiki-conf.h
index 9c3e1f52e..d45a58057 100644
--- a/platform/mbxxx/contiki-conf.h
+++ b/platform/mbxxx/contiki-conf.h
@@ -181,7 +181,7 @@ typedef unsigned long clock_time_t;
 
 #define CLOCK_CONF_SECOND 1000
 
-typedef unsigned long long rtimer_clock_t;
+typedef unsigned long rtimer_clock_t;
 #define RTIMER_CLOCK_LT(a,b)     ((signed short)((a)-(b)) < 0)
 
 /* LEDs ports MB8xxx */