I got an iPhone 2g off Craigslist today and upgraded it to 3.1.2 through iTunes. After it was upgraded I jailbroke and activated the phone succsesfully. Wifi works, all apps work. However I have no signal bars. I installed ultrasn0w through cydia and now the phone says searching for a few minutes, then no service.

I then downgraded phone to 3.0 through iTunes and jailbroke and activated phone. Same result, no signal bars. Phone currently has version 3.0 and surfs web fine through wifi but no signal at all.

Someone please point me in the right direction. I am interested in baseband options, but do not know enough about baseband to fully believe this is the cause or I should start downloading programs to upgrade/downgrade.

Help!!

Ultrasn0w does not work with 2G iPhones. If the phone was unlocked under OS 1.x or was never unlocked then you need to use bootneuter to unlock a 2G iPhone. This is included with Redsn0w and PwnageTool. Or you can install it from Cydia.

Be very careful with BootNeuter, this is a permanent unlock and you should never restart the phone during the unlocking process.

Set your screen lock to never before you run boot neuter and just make the minimum changes required to unlock. It can take a few minutes to reflash the baseband, during this time you must not interrupt the process.

Have you tried placing the phone in Airplane Mode for maybe 30 secs and then turn it back on? This was a little trick I got from Apple iPhone Support. Hope it works for you.