I just had changed main board on my P6810 and Samsung sent my tablet back with ICS 4.0.4. Everything okay except that after one day is no lockscreen and no shutdown menu when I press the power button. I factory reset it few times (from menu and from restore mode). Same thing. After reinstall comes an extra shortcut named "factory mod". But still no lockscreen or shutdown menu. Settings seemed OK. "Factory mod" open a blank page with a calculator keyboard (numbers and signs) on the bottom. Anyone have any idea. Thanks.