diff --git a/arm64-build.sh b/arm64-build.sh
index 2372b4a..0be83fe 100755
--- a/arm64-build.sh
+++ b/arm64-build.sh
@@ -35,7 +35,7 @@ echo "IP: \4" >> /etc/issue
 EOT
 
 echo "Unmounting second partition"
-sudo umount mnt
+sudo umount mnt -R
 
 echo "Compressing resulting image"
 xz $RASPIOS_IMG