diff --git a/libmicrokit/src/main.c b/libmicrokit/src/main.c
index f05c8f28..3ba35a35 100644
--- a/libmicrokit/src/main.c
+++ b/libmicrokit/src/main.c
@@ -58,6 +58,7 @@ static void handler_loop(void)
             tag = seL4_ReplyRecv(INPUT_CAP, reply_tag, &badge, REPLY_CAP);
         } else if (have_signal) {
             tag = seL4_NBSendRecv(signal, signal_msg, INPUT_CAP, &badge, REPLY_CAP);
+            have_signal = false;
         } else {
             tag = seL4_Recv(INPUT_CAP, &badge, REPLY_CAP);
         }