About 5 months ago, I unlocked and jailbroke a 1.1.4OOB using iLiberty and boot neuter for a friend. Up until 3 weeks ago, the iPhone was working fine. Now for no reason, he only gets 1 bar max but most of the time, its shows NO SERVICE

I pulled the SIM out and replaced with a a known good card, same thing. I upgraded the software to 2.1 and the phone still shows NO SERVICE, wireless and bluetooth works fine

I'm thinking of backing the whole thing out to 1.1.4 and downgrading the baseband with a view to getting it working

Any help or anything would be great!