Arghh!.
Just about got my 1.4 back with a signal after earlier upgrade attempt- been through every firmware reload and finaly got 1.1.3 signal back using bricktool signal fix, then reloaded 1.4 and unlock with iliberty+ and signal came back too.
Those that have sucesfully upgraded to 2.0 from an unlocked etc. firmware- did you have 4.6 boot loader or the older 3.9? My iphone was originaly 1.1.2, but has had many different reflashes/downgrades including ziphone which downgraded bootloader.
I tried a second time to go to 2.0, but got similar issue, itunes doesnt come up with activation screen- just says Itunes cant read the sim or there is simlock.
Im wondering if I should restore bootloader to 4.6 and then try?