am living in India, hav a BB pearl 8100(RED) bought frm USA by my cousin. It is an unlocked one. It has a T Mobile Logo printed below keypad and AT&T logo during logon and shutdown screen. I am afraid that after upgrade it will get locked!!! Please tell me if there is anything like tht.

I also want to know what are things tht I wont b able to do on my unlocked phone when compared to a locked one.