[How-To] Rooting LS670ZVD with GingerBreak (no reverting and OTA works too!)

I trying to do the same on my xperia x10i (2.3.3)

$ chmod 777 /data/local/tmp/*
chmod 777 /data/local/tmp/*
$ mount -o remount,rw -t yaffs2 /system /system
mount -o remount,rw -t yaffs2 /system /system
mount: Operation not permitted


on step 8 I have a problem. Could any one help on this.
Thank You In Advance.