diff --git a/lib/aos/aos_urpc.c b/lib/aos/aos_urpc.c
index 71738a6..011e48b 100644
--- a/lib/aos/aos_urpc.c
+++ b/lib/aos/aos_urpc.c
@@ -56,7 +56,7 @@ errval_t do_aos_urpc(
     // wait until the rpc call completes
     while(rpc->meta->call_in_progress) {
         // yield the thread because there might be useful stuff to do...
-        // thread_yield();
+        thread_yield();
     }
 
     // memory barrier
@@ -180,9 +180,8 @@ int urpc_server(void *arg) {
     while (true) {
         // wait until an rpc call arrives
         while(urpc->meta->call_in_progress == false) {
-            // sleep for a bit while there is nothing to do
-            // barrelfish_usleep(100);
-            // thread_yield();
+            // yield the thread because there might be useful stuff to do...
+            thread_yield();
         }
 
         // memory barrier