Preparing to sell an AT&T 3GS, but it's gotten a little bogged down with tweaks, test-apps, etc. It's running on an iPad baseband in the 3x range and iOS 3x. (really old school!) I want to start from a factory setting, then install a fresh jailbreak and unlock if I can't get an IMEI for it. Any precautions, tips, tricks would also be welcome.