diff --git a/deploy/pi-gen/stage-betterframe-client/01-install-kiosk/00-run.sh b/deploy/pi-gen/stage-betterframe-client/01-install-kiosk/00-run.sh
index 92ab34c..140a1ee 100755
--- a/deploy/pi-gen/stage-betterframe-client/01-install-kiosk/00-run.sh
+++ b/deploy/pi-gen/stage-betterframe-client/01-install-kiosk/00-run.sh
@@ -1,8 +1,9 @@
 #!/bin/bash -e
-# Host-side (runs outside chroot, before 01-run-chroot.sh). Stages every
-# file from the sub-stage's files/ dir into the chroot at /tmp/bf-files
-# so the chroot script can install them. Files dir is populated by CI
-# (build.yml's "Stage files for pi-gen" step).
+# Host-side (runs outside chroot, before 01-run-chroot.sh). Pi-gen sets
+# cwd to the sub-stage directory and exposes ROOTFS_DIR. Bulk-copy this
+# sub-stage's files/ into the chroot at /tmp/bf-files so 01-run-chroot.sh
+# can install them. files/ is populated by CI (build.yml's "Stage files
+# for pi-gen" step).
+SUB_STAGE_DIR="$(cd "$(dirname "$0")" && pwd)"
 install -d "${ROOTFS_DIR}/tmp/bf-files"
-cp -r "${BASE_DIR}/stage-betterframe-client/01-install-kiosk/files/." \
-      "${ROOTFS_DIR}/tmp/bf-files/"
+cp -r "${SUB_STAGE_DIR}/files/." "${ROOTFS_DIR}/tmp/bf-files/"