Hello, I bought 3gs iphone unlocked and start using with T-mobile. I donot know what version of OS comes with the original 3 gs. Few days back I want to sync some songs to my iphone through itunes by hooking it to computer. While syncronizing songs from iTunes, i unintentionally clicked OK to update my iphone software when presented. Now my 3 gs iphone is not working. It is not even recognizing my sim card. Can anyone point me somewhere where I can get back my original version of OS back. Is it possible to get it back or I cannot. Please help. I am not much knowledgeable about iphones.