diff --git a/os/rt/src/chschd.c b/os/rt/src/chschd.c
index d1c42e55d..de6d1520a 100644
--- a/os/rt/src/chschd.c
+++ b/os/rt/src/chschd.c
@@ -430,7 +430,7 @@ void chSchWakeupS(thread_t *ntp, msg_t msg) {
     (void) chSchReadyI(ntp);
   }
   else {
-    otp = chSchReadyI(otp);
+    otp = chSchReadyAheadI(otp);
 
     /* Handling idle-leave hook.*/
     if (otp->prio == IDLEPRIO) {
diff --git a/readme.txt b/readme.txt
index ef360aa21..6b809707a 100644
--- a/readme.txt
+++ b/readme.txt
@@ -101,6 +101,8 @@
 - 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 reduced time slices in RT (bug #1034)
+       (backported to 19.1.3)(backported to 18.2.3).
 - FIX: Fixed GCC scatter files alignment problem (bug #1033)
        (backported to 19.1.3)(backported to 18.2.3).
 - FIX: Fixed long intervals fail when interval type is larger than time type