How to unlock ma Iphone 3gs???????

[chandre]

I'm from Sri Lanka and i'm using an iphone 3gs which I bought from USA.(T-mobile).I used it on 4.3.3 over 1 year, but when after i updating it to 5.1 it needed to be unlocked.so I again downgraded it to 4.3.1.Now I have jail broken it.But the only problem is unlocking.

The case is baseband has been upgraded.i don't know what was the previous baseband.but now it displays it as 06.15.any how it does not works with ultrasn0w.whenever i install a sim in it, iphone searches for network and says No Service.

When a gave it a repair shop they said that the baseband have to be downgraded and that's too hard 2 do.

I doont know how to downgrade 3gs baseband and get my i phone back.now it has become a good Ipod touch.errrrrrr!!!!!!!PLZZZZZZZZZ anybody help mee????

 

[Jmills87]

Baseband cannot be downgraded. The most likely problem is that you upgraded to 5.1 using a factory firmware. This corrupts the baseband. If you are on the 06.15.00 baseband you must always restore a custom firmware when upgrading otherwise the baseband will be corrupted. Upgrade back to 5.1 and perform the tethered jailbreak, then reinstall the iPad baseband and download Ultrasn0w again.