diff --git a/ci/micropython.sh b/ci/micropython.sh
index 0a4b53a..a42ac5c 100644
--- a/ci/micropython.sh
+++ b/ci/micropython.sh
@@ -30,7 +30,7 @@ function micropython_clone {
 function micropython_build_mpy_cross {
     cd micropython/mpy-cross
     ccache --zero-stats || true
-    CROSS_COMPILE="ccache " make
+    CROSS_COMPILE="ccache " USER_C_MODULES= make
     ccache --show-stats || true
     cd ../../
 }