diff --git a/tests/posix_semaphore/main.c b/tests/posix_semaphore/main.c
index 764aeb684939..344785132755 100644
--- a/tests/posix_semaphore/main.c
+++ b/tests/posix_semaphore/main.c
@@ -236,16 +236,16 @@ void test3(void)
     sem_post(&s1);
 }
 
-#ifdef BOARD_NATIVE
-/* native can sometime take more time to respond as it is not real time */
-#define TEST4_TIMEOUT_EXCEEDED_MARGIN (300)
-#elif CPU_FAM_NRF51
-/* nrf51 based boards needs a slightly higher margin value. Using 105us makes
- test4 result more reliable. */
-#define TEST4_TIMEOUT_EXCEEDED_MARGIN (105)
-#else
-#define TEST4_TIMEOUT_EXCEEDED_MARGIN (100)
-#endif /* BOARD_NATIVE */
+/*
+ * Allowed margin for waiting too long.
+ *
+ * Waiting too short is forbidden by POSIX, but is checked elsewhere.
+ *
+ * This allows waiting a little (0.1%) longer than exactly 1000000us.
+ * The value should be large enough to not trip over timer inaccuracies, but
+ * small enough to catch any fundamental problems.
+ */
+#define TEST4_TIMEOUT_EXCEEDED_MARGIN (1000)
 
 void test4(void)
 {