I have a 3GS that I no longer use and a friend would like to buy it. I do not know a whole lot about unlocking iPhones, but he would like to unlock it and explained to me that he can do it with the current baseband version. He also said that if I update the phone in iTunes it will upgrade the baseband. Of course, I'd like to delete all my personal data from the phone. The quickest method I have found is the "Erase All Content and Settings" options under Reset in Settings. So my question is: if I do this, will it delete all my data from the phone and keep it at the current software version which is 3.1.2? Or will it completely wipe the phone to exactly as it was out of the box and the phone will have to be updated to 4.1.2?