diff --git a/scripts/quick-test-this-branch.sh b/scripts/quick-test-this-branch.sh
index aef69d46..13ec0d13 100755
--- a/scripts/quick-test-this-branch.sh
+++ b/scripts/quick-test-this-branch.sh
@@ -2,46 +2,23 @@
 
 set -eux
 
+
 src="$(dirname "$(dirname "$(readlink -f "${0}")")")"
+
+LIVEFS_EDITOR="${LIVEFS_EDITOR-$src/livefs-editor}"
+[ -d $LIVEFS_EDITOR ] || git clone https://github.com/mwhudson/livefs-editor $LIVEFS_EDITOR
+
+LIVEFS_EDITOR=$(readlink -f $LIVEFS_EDITOR)
+
 old_iso="$(readlink -f "${1}")"
 new_iso="$(readlink -f "${2}")"
 
 tmpdir="$(mktemp -d)"
 cd "${tmpdir}"
 
-_MOUNTS=()
+PYTHONPATH=$LIVEFS_EDITOR python3 -m livefs_edit $old_iso /dev/null --setup-rootfs \
+          --shell 'cp rootfs//var/lib/snapd/seed/snaps/subiquity_*.snap '$tmpdir'/old.snap'
 
-do_mount_existing () {
-    local mountpoint="${!#}"
-    mount "$@"
-    _MOUNTS=("${mountpoint}" "${_MOUNTS[@]+"${_MOUNTS[@]}"}")
-}
+$src/scripts/slimy-update-snap.sh old.snap subiquity_new.snap
 
-do_mount () {
-    local mountpoint="${!#}"
-    mkdir "${mountpoint}"
-    do_mount_existing "$@"
-}
-
-clean_mounts () {
-    for m in "${_MOUNTS[@]+"${_MOUNTS[@]}"}"; do
-        umount "${m}"
-    done
-    _MOUNTS=()
-}
-
-cleanup () {
-    clean_mounts
-    rm -rf "${tmpdir}"
-}
-
-trap cleanup EXIT
-
-do_mount $old_iso old_iso
-do_mount old_iso/casper/installer.squashfs installer
-
-$src/scripts/slimy-update-snap.sh installer/var/lib/snapd/seed/snaps/subiquity_*.snap subiquity_new.snap
-
-clean_mounts
-
-$src/scripts/inject-subiquity-snap.sh $old_iso subiquity_new.snap $new_iso
+PYTHONPATH=$LIVEFS_EDITOR python3 -m livefs_edit $old_iso $new_iso --inject-snap subiquity_new.snap