I've looked pretty hard for information about this, but it seems to be a fairly unique problem. I have a jailbroken and unlocked iPhone 4 running 4.3.3, and I need the unlock to run my phone in Canada where I live now. Unfortunately, my screen just got completely destroyed. The phone still turns on, but iTunes cannot sync it. Every time I plug it in to my Mac, iTunes says it needs to restore the phone. Apple is sending me a refurbished replacement phone to exchange for my broken phone, which will be running the latest software and surely the newest baseband firmware, so I won't be able to unlock it. Is there anything I can do to revert the new phone? I have a backup of my current iPhone in iTunes, can I swap that in? or is the firmware upgrade permanent? Thanks so much for any insight into this problem.