diff --git a/src/platform/SITL/sitl.c b/src/platform/SITL/sitl.c
index c8ac5a9784..da8cfd3689 100644
--- a/src/platform/SITL/sitl.c
+++ b/src/platform/SITL/sitl.c
@@ -748,3 +748,13 @@ void unusedPinsInit(void)
 {
     printf("unusedPinsInit\n");
 }
+
+void IOHi(IO_t io)
+{
+    UNUSED(io);
+}
+
+void IOLo(IO_t io)
+{
+    UNUSED(io);
+}