Iphone 3g restoring/updating question. Please help

[Kfchotwings]

I have a t mobile 3g iphone that is on 4.1 running 6.15.00 firmware. Just recently i have had no signal and no service. I usually get full bars in my area. I have tried removing the sim, turning off the iphone, charging it, resetting network, putting it into airplane mode, and nothing is working. Can i update my iphone or will i lose the ability to have it unlocked? Or should i restore it and then unlock it again? I need help immediately because my phone gets 1 bar of signal at best right now.

[iYeow]

You can only restore to custom firmware of 4.2.1 or higher. Your signal bars depends on your ipad baseband and you can unlock again with Ultrasn0w.
The thing here is restoring to custom firmware will not touch your baseband, you may still get low signal as before. Try it out and see if it improves.