Hi .. I using iphone 4. a while ago I was insatlled siwrly mms. when finished installed dat applications suddenly its reboot and stuck at apple logo. now i want to restore it using iTunes. when i connect to iTunes, iTunes prompted me to restore and update. since mine was at&t set , I do not think it necessary to update the ios 5. (because I heard ios5 still not stable for at&t sets). so how do I restore back to original firmware without any update?TQ

I have two iphones. how I want to restore application from 'A' to b iphone to 'B' iphone using iTunes?