diff --git a/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh b/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh
index 84f1219f..0cb2ee21 100755
--- a/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh
+++ b/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh
@@ -12,6 +12,9 @@ set -e
 ROOT_DEV="$(findmnt / -o source -n)"
 ROOT_DEV_NAME=${ROOT_DEV##*/}
 ROOT_DEV_SLAVE=$(find /sys/block/"${ROOT_DEV_NAME}"/slaves -mindepth 1 -print -quit 2>/dev/null || true)
+while [ -d "${ROOT_DEV_SLAVE}/slaves" ]; do
+	ROOT_DEV_SLAVE=$(find "${ROOT_DEV_SLAVE}"/slaves -mindepth 1 -print -quit 2>/dev/null || true)
+done
 if [ -n "${ROOT_DEV_SLAVE}" ]; then
 	ROOT_DEV=/dev/${ROOT_DEV_SLAVE##*/}
 fi