diff --git a/applications/message_handler/main.cpp b/applications/message_handler/main.cpp
index 9f7c7cc..9b36f84 100644
--- a/applications/message_handler/main.cpp
+++ b/applications/message_handler/main.cpp
@@ -128,9 +128,11 @@
 
 namespace {
 
+#ifdef MHU_IRQ
 void mailboxIrqHandler() {
     mailbox.handleMessage();
 }
+#endif
 
 void inferenceTask(void *pvParameters) {
     printf("Starting inference task\n");
diff --git a/applications/message_handler/message_handler.cpp b/applications/message_handler/message_handler.cpp
index 7401546..f9f7304 100644
--- a/applications/message_handler/message_handler.cpp
+++ b/applications/message_handler/message_handler.cpp
@@ -375,7 +375,7 @@
 }
 
 void OutgoingMessageHandler::readCapabilties(ethosu_core_msg_capabilities_rsp &rsp) {
-    rsp = {0};
+    rsp = {};
 
 #ifdef ETHOSU
     struct ethosu_driver_version version;