3gs iphone

[sadavennam]

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.

 

[Crystal-RX]

Since you update to the latest firmware which is 4.3.1 as well as latest baseband. Your phone is now locked to AT&T network. Currently, there is no unlock for the latest baseband.

 

[Applejuiced]

Good job.
How do people keep updating their JB and software unlocked iphones and think everything will still work fine?
Your unlock is gone now, you can either wait till there's a new unlock maybe down the road, or either sell it or get a AT&T postpaid or prepaid account.
You wont be able to use it with your Tmobile sim for a while.