diff --git a/tools/autobuild/autobuild.sh b/tools/autobuild/autobuild.sh
index 7073152df7..c24c4b3a9a 100755
--- a/tools/autobuild/autobuild.sh
+++ b/tools/autobuild/autobuild.sh
@@ -48,6 +48,9 @@ git -C ${MICROPY_AUTOBUILD_MICROPYTHON_REPO}/lib/pico-sdk submodule update --ini
 ########################################
 # Build all firmware
 
+# Fail on some things which are warnings otherwise
+export MICROPY_MAINTAINER_BUILD=1
+
 pushd ${MICROPY_AUTOBUILD_MICROPYTHON_REPO}
 
 # build cross compiler
diff --git a/tools/ci.sh b/tools/ci.sh
index 8f045639b8..fbb9ae5abf 100755
--- a/tools/ci.sh
+++ b/tools/ci.sh
@@ -9,6 +9,9 @@ fi
 # Ensure known OPEN_MAX (NO_FILES) limit.
 ulimit -n 1024
 
+# Fail on some things which are warnings otherwise
+export MICROPY_MAINTAINER_BUILD=1
+
 ########################################################################################
 # general helper functions