diff --git a/src/core/sys.c b/src/core/sys.c
index d1fbda4e..cb5e86a7 100644
--- a/src/core/sys.c
+++ b/src/core/sys.c
@@ -97,7 +97,7 @@ sys_mbox_fetch(sys_mbox_t mbox, void **msg)
       arg = tmptimeout->arg;
       memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
       if (h != NULL) {
-        LWIP_DEBUGF(SYS_DEBUG, ("smf calling h=%p(%p)\n", (void*)&h, arg));
+        LWIP_DEBUGF(SYS_DEBUG, ("smf calling h=%p(%p)\n", *(void**)&h, arg));
         h(arg);
       }
 
@@ -154,7 +154,7 @@ sys_sem_wait(sys_sem_t sem)
       arg = tmptimeout->arg;
       memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
       if (h != NULL) {
-        LWIP_DEBUGF(SYS_DEBUG, ("ssw h=%p(%p)\n", (void*)&h, (void *)arg));
+        LWIP_DEBUGF(SYS_DEBUG, ("ssw h=%p(%p)\n", *(void**)&h, (void *)arg));
         h(arg);
       }
 
@@ -203,7 +203,7 @@ sys_timeout(u32_t msecs, sys_timeout_handler h, void *arg)
   timeouts = sys_arch_timeouts();
 
   LWIP_DEBUGF(SYS_DEBUG, ("sys_timeout: %p msecs=%"U32_F" h=%p arg=%p\n",
-    (void *)timeout, msecs, (void*)&h, (void *)arg));
+    (void *)timeout, msecs, *(void**)&h, (void *)arg));
 
   if (timeouts == NULL) {
     LWIP_ASSERT("sys_timeout: timeouts != NULL", timeouts != NULL);
@@ -264,13 +264,15 @@ sys_untimeout(sys_timeout_handler h, void *arg)
     if ((t->h == h) && (t->arg == arg)) {
       /* We have a match */
       /* Unlink from previous in list */
-      if (prev_t == NULL)
+      if (prev_t == NULL) {
         timeouts->next = t->next;
-      else
+      } else {
         prev_t->next = t->next;
+      }
       /* If not the last one, add time of this one back to next */
-      if (t->next != NULL)
+      if (t->next != NULL) {
         t->next->time += t->time;
+      }
       memp_free(MEMP_SYS_TIMEOUT, t);
       return;
     }