diff --git a/import-stx b/import-stx
index 61854e29..ce37a3d1 100644
--- a/import-stx
+++ b/import-stx
@@ -69,6 +69,11 @@
 #     without the "--rebuild" flag.
 #     Default: master-debian-latest
 
+#   STX_PREBUILT_BUILDER_IMAGE_PREFIX
+#     Download pre-built images from this registry/prefix. This is used by "stx-init-env"
+#     without the "--rebuild" flag. If not empty, this must end with "/".
+#     Default:starlingx/
+
 notice_warn () {
     local tty_on tty_off
     if [[ -t 2 ]] ; then
diff --git a/stx-init-env b/stx-init-env
index d4d17d09..0c6e62a5 100755
--- a/stx-init-env
+++ b/stx-init-env
@@ -54,7 +54,7 @@ HELM=helm
 DOCKER=docker
 PYTHON3=python3
 KUBECTL=kubectl
-DOCKER_PREFIX="starlingx/"
+DOCKER_PREFIX=${STX_PREBUILT_BUILDER_IMAGE_PREFIX:-'starlingx/'}
 DOCKER_IMAGES="stx-builder stx-pkgbuilder stx-lat-tool stx-aptly"
 DOCKER_TAG="$STX_PREBUILT_BUILDER_IMAGE_TAG"