diff --git a/docker.mk b/docker.mk
index f9ab4b3..3143a6a 100644
--- a/docker.mk
+++ b/docker.mk
@@ -74,6 +74,7 @@
 		-e "FETCH_PACKAGES=$(FETCH_PACKAGES)" \
 		-e "PACKAGES_REVISION=$(PACKAGES_REVISION)" \
 		-e "HEADLESS_BUILD=$(HEADLESS_BUILD)" \
+		-e "IS_EXTERNAL=$(IS_EXTERNAL)" \
 		-e "http_proxy=$(http_proxy)" \
 		aiy-board-builder \
 		/bin/bash -c \