diff --git a/build/root/Makefile b/build/root/Makefile
index de60c5edb4b..46fea1fd332 100644
--- a/build/root/Makefile
+++ b/build/root/Makefile
@@ -231,6 +231,7 @@ define TEST_E2E_NODE_HELP_INFO
 #  IMAGE_SERVICE_ENDPOINT: remote image endpoint to connect to, to prepull images.
 #    Used when RUNTIME is set to "remote".
 #  IMAGE_CONFIG_FILE: path to a file containing image configuration.
+#  IMAGE_CONFIG_DIR: path to image config files.
 #  SYSTEM_SPEC_NAME: The name of the system spec to be used for validating the
 #    image in the node conformance test. The specs are located at
 #    test/e2e_node/system/specs/. For example, "SYSTEM_SPEC_NAME=gke" will use