diff --git a/postrecoveryboot.sh b/postrecoveryboot.sh
index 0137371..6342351 100755
--- a/postrecoveryboot.sh
+++ b/postrecoveryboot.sh
@@ -2,6 +2,6 @@
 
 sleep 2
 
-if [[ ! `grep clk= /proc/cmdline` ]]; then
+if [[ "`grep clk= /proc/cmdline`" == "" ]]; then
 sed -i 's/\/boot\t\tmtd/\/boot\t\tyaffs2/g' /etc/recovery.fstab
 fi