diff --git a/Makefile b/Makefile
index c4b4a2c..3c80ace 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,7 @@ TEMPLATE_ENV_WHITELIST += \
 	TEMPLATE_FLAVOR_DIR TEMPLATE_OPTIONS APPMENUS_DIR \
 	VERBOSE DEBUG PATH BUILDER_DIR SRC_DIR DISCARD_PREPARED_IMAGE \
 	TEMPLATE_ROOT_WITH_PARTITIONS USE_QUBES_REPO_VERSION \
-	USE_QUBES_REPO_TESTING BUILDER_TURBO_MODE REPO_PROXY
+	USE_QUBES_REPO_TESTING BUILDER_TURBO_MODE REPO_PROXY REPO_BASEURL_PREFIX
 
 # Make sure names are < 32 characters, process aliases
 fix_up := $(shell TEMPLATE_NAME=$(TEMPLATE_NAME) ./builder_fix_filenames)