diff --git a/firmware/kernel/mutex.c b/firmware/kernel/mutex.c
index fc49cc6d09..876b704b51 100644
--- a/firmware/kernel/mutex.c
+++ b/firmware/kernel/mutex.c
@@ -103,6 +103,12 @@ void mutex_unlock(struct mutex *m)
     }
 
     const int oldlevel = disable_irq_save();
+    /* Tranfer of owning thread is handled in the wakeup protocol
+     * if priorities are enabled otherwise just set it from the
+     * queue head. */
+#ifndef HAVE_PRIORITY_SCHEDULING
+    m->blocker.thread = thread;
+#endif
     unsigned int result = wakeup_thread(thread, WAKEUP_TRANSFER);
     restore_irq(oldlevel);