you dont need to flash it.
call att and ask for the unlock code.
when you put the tmobile sim code in it will ask for the network unlock code. enter the code att gave you and you can use it for tmobile.
you dont need to flash it.
call att and ask for the unlock code.
when you put the tmobile sim code in it will ask for the network unlock code. enter the code att gave you and you can use it for tmobile.