diff --git a/init.sh b/init.sh
index 4103121..1e7c46f 100755
--- a/init.sh
+++ b/init.sh
@@ -167,7 +167,7 @@ fi
 # unmount if device is mounted
 umount_device (){
 local mounted_part=$(mount | grep "${1}[0-9]" | awk '{print $3}')
-if [ ! -z mounted_part ]
+if [ ! -z $mounted_part ]
 then
     for part in $mounted_part
     do