I have two AT&T 16gb Iphones 4 that are JB IOS 4.3.3. In attempting to sell these, I wanted to erase all the data on them. When I try to use the Erase All in settings I just get the Apple Logo with a status bar that doesnt move. I Can reset them to get them back on but need a way to Erase al of the info and if possible keeping 4.3.3 because the potential buyer wants to keep the JB. Any suggestions?