diff --git a/sched/semaphore/sem_tickwait.c b/sched/semaphore/sem_tickwait.c
index c6d4217395..9f219bc571 100644
--- a/sched/semaphore/sem_tickwait.c
+++ b/sched/semaphore/sem_tickwait.c
@@ -100,8 +100,9 @@ int nxsem_tickwait(FAR sem_t *sem, uint32_t delay)
 
   if (delay == 0)
     {
-      /* Return the errno from nxsem_trywait() */
+      /* Timed out already before waiting */
 
+      ret = -ETIMEDOUT;
       goto out;
     }
 
@@ -149,7 +150,7 @@ out:
 
 int nxsem_tickwait_uninterruptible(FAR sem_t *sem, uint32_t delay)
 {
-  clock_t end = clock_systime_ticks() + delay;
+  clock_t end = clock_systime_ticks() + delay + 1;
   int ret;
 
   for (; ; )