I am selling my iPhone4 with iOS 4.1. I need to wipe the phone. I jailbroke it already. I read online that I can use the "Restore" function in iTunes and it would wipe the iPhone4. However, it wold restore to a higher iOS version and may update the baseband. Now, how do I wipe my iPhone4 correctly so that it would wipe the jailbreak and also keep the baseband and iOS 4.1 version. Thanks!