put a non-accepted sim card, turn the phone on, and when you receive the message "insert correct card" or something like this, press: *#9998*3323# press "exit" and a menu will appear choose the 7th option from this menu wait until the phone reboots (it may take a while), don't worry if you will see some weird things on the screen. you will need to do that each time you put in the phone a non-accepted sim card (in that way, you can keep the warranty ) have luck
