I recently got a replacement Sprint iPhone 4S from Apple. My last one was carrier unlocked. I want to do the same with this one but doing the usual restore through iTunes it's forcing me to upgrade to iOS 7. I like iOS 7 but since I'm planning on selling this in the next month or so I'd like to keep it where it is now to help increase the value or demand for it. I'm not sure if this will help, if it absolutely will not please let me know and I'll upgrade. Is there anyway to do this without upgrading to 7? I tried doing an erase and restore from the phone and that did not work. Anything else I'm missing?