diff --git a/tests/crypto/test_hmac_prng/prj.mdef b/tests/crypto/test_hmac_prng/prj.mdef
index 6428ab03900..4ded1cecf5c 100644
--- a/tests/crypto/test_hmac_prng/prj.mdef
+++ b/tests/crypto/test_hmac_prng/prj.mdef
@@ -2,4 +2,4 @@
 
 % TASK NAME          PRIO ENTRY           STACK GROUPS
 % ====================================================
-  TASK tStartTask       5 main            51200 [EXE]
+  TASK tStartTask       5 main            41200 [EXE]