I'm with Sprint and used upgrade on one of my lines to to get an iphone. I will give it to my brother to use while abroad. I will activate another phone on his line so we can still make use of the line while he's away, and the iphone 4S will not be linked to any Sprint line. My account met the criteria for the unlock and I have already gotten the "Congratulations your phone is unlocked message through itunes." I have purchased a Rogers test SIM and though it is not provisioned it appears to be recognized by the iphone when I go to into Settings-About-Carrier-Rogers. My brother will be using a sim card from a carrier of the country he's traveling to. If my brother has to factory reset or update firmware on the iphone at any point while abroad and get it reactivated through itunes or wifi do you think it would reverse the unlock?