diff --git a/alpine-install-on-disk.sh b/alpine-install-on-disk.sh
index a135c6b..ecbd32e 100755
--- a/alpine-install-on-disk.sh
+++ b/alpine-install-on-disk.sh
@@ -151,6 +151,7 @@ case "$BOOT_VIA" in
         run_root mkdir /boot/EFI/boot
         run_root cp /boot/EFI/alpine/grubx64.efi /boot/EFI/boot/bootx64.efi
         run_root cp /boot/grub/grub.cfg /boot/EFI/boot/
+        sudo umount ${rootfs_tmpdir}/boot
         ;;
 esac