Remove Ad kindle4(NT)

http://www.youtube.com/watch?v=XZEhsCKgMHw
http://www.youtube.com/watch?v=fG_pGDMsAYo
mntroot rw
mkdir /mnt/us/screensaver
mount /dev/mmcblk0p1 /mnt/base-mmc
rm -rf /mnt/base-mmc/opt/amazon/screen_saver/600x800
ln -sfn /mnt/us/screensaver /mnt/base-mmc/opt/amazon/screen_saver/600x800
rm -rf /mnt/base-mmc/opt/amazon/screen_saver/adunits/600x800
ln -sfn /mnt/us/screensaver /mnt/base-mmc/opt/amazon/screen_saver/adunits/600x800
rm -rf /mnt/us/system/.assets
exit
on kindle go to
Settings>>Restart
Don't connect Internet Because kindle will download Ads.
Sorry for my English.