diff --git a/os/rt/include/chtime.h b/os/rt/include/chtime.h
index c975d10..99ce8d8 100644
--- a/os/rt/include/chtime.h
+++ b/os/rt/include/chtime.h
@@ -472,11 +472,11 @@ static inline time_usecs_t chTimeI2US(sysinterval_t interval) {
 static inline systime_t chTimeAddX(systime_t systime,
                                    sysinterval_t interval) {
 
-#if CH_CFG_ST_RESOLUTION != CH_CFG_INTERVALS_SIZE
-  chDbgCheck(interval <= (sysinterval_t)((systime_t)-1));
+#if CH_CFG_ST_RESOLUTION < CH_CFG_INTERVALS_SIZE
+  return  systime + (systime_t)(interval % ((sysinterval_t)1 << CH_CFG_ST_RESOLUTION));
+#else
+  return systime + interval;
 #endif
-
-  return systime + (systime_t)interval;
 }
 
 /**