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 0cb2ee21..8770677c 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
@@ -9,7 +9,7 @@
 
 set -e
 
-ROOT_DEV="$(findmnt / -o source -n)"
+ROOT_DEV="$(readlink -f "$(findmnt / -o source -n)")"
 ROOT_DEV_NAME=${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