I have (2) iPhone 3Gs, called AT&T, and got it factory unlocked. However, in order to complete the factory unlock i have to restore. Both iPhones are on iOS 4/5. 1 iPhone has a baseband of 6.15.00 and another has 5.16.05. I want to go ahead and restore them but im afraid I might brick them and not be able to sell them. I know for baseband 6.15.00, i heard you can downgrade the baseband. and restore from there. can i restore the other iphone that has a baseband of 5.16.05, is it safe? please let me know so i can go ahead restore to iOS 6 and have my phones officially factory unlocked. Im selling both of the iPhone 3Gs 16gb.. if you guys need additional info let me know such as serial or IMEI numbers