No service!! Plz help!

[davetj]

I have a jailbroken/unlocked 3g iphone with 2.2.1 firmware.
I accidently upgraded to newest 3.0 version in itunes, since then I get no service or no sim card sign on it.
So I downgraded back to 2.2.1 and unlocked it again but it still gives me no service and I am stuck right now.
It now works with at&T simcard but gives me no service with t-mobile simcard with turbo sim.
Can anyone please give me a solution?? I alreay spent more six hours of serching for solutions today but came up with nothing.
Please help!

[oblivior72]

Ok here is what you need to do

1. Go back to 3.0 (Do a fresh installation on everything)
2. Jailbreak the device either using Quickpwn or redsnow or pwnagtools
3. Add the Ultrasn0w repo in cydia
4. install ultrasn0w
5. get rid of turbosim....you dont need it just put the tmobile sim card
6. and you should be set to go

there are isntructions all over the place on how to do this. google "Dev team blog" and it will take you their site which tells you a bit more detailed explanation.

Hope this helps