I am totally new to a Note 3. Bought one yesterday which is an AT&T one not unlocked. How can I check if it is having region lock on or not? Previous owner was using it on AT&T. I have read that once you use it on original carrier, the region lock is disabled. Is this true? Does the lock gets reset when the phone is factory reset? How can I check if the region lock is active or not? I can purchase an unlock code. But they insist that the region lock needs to be off before entering the code. Any help is appreciated.