diff --git a/os/rt/include/chvt.h b/os/rt/include/chvt.h
index 70c3182e6..f1bb4d9f2 100644
--- a/os/rt/include/chvt.h
+++ b/os/rt/include/chvt.h
@@ -450,7 +450,7 @@ static inline void chVTDoTickI(void) {
   ch.vtlist.next->delta -= nowdelta;
 
   /* Recalculating the next alarm time.*/
-  delta = chTimeDiffX(now, chTimeAddX(ch.vtlist.lasttime, vtp->delta));
+  delta = vtp->delta - chTimeDiffX(ch.vtlist.lasttime, now);
   if (delta < (sysinterval_t)CH_CFG_ST_TIMEDELTA) {
     delta = (sysinterval_t)CH_CFG_ST_TIMEDELTA;
   }
diff --git a/readme.txt b/readme.txt
index f8e6a84a1..385ba7e8a 100644
--- a/readme.txt
+++ b/readme.txt
@@ -96,6 +96,8 @@
 - HAL: Added a new interface for range-finder devices (used by EX).
 - HAL: Added mcuconf.h updater tool for STM32F407 (backported to 19.1.1).
 - NIL: Integrated NIL 4.0.
+- FIX: Fixed long intervals fail when interval type is larger than time type
+       (bug #1031)(backported to 19.1.3)(backported to 18.2.3).
 - FIX: Fixed Round Robin check missing when in tick-less mode (bug #1030)
        (backported to 19.1.3)(backported to 18.2.3).
 - FIX: Fixed RCC_AHB1ENR_BKPSRAMEN not present in all STMF4xx devices