2G iPhones previously unlocked with IPSF (iPhoneSimFree) still work after patching them with the new PwnageTool 2.0 from iPhone-dev team. I successfully updated my 1.1.4 IPSF iPhone with the original 3.9 bootloader to the new 2.0 firmware without any problems. I was using ZiPhone to update to 1.1.4 but that didn’t seem to be a problem. Signal.app is not needed as PwnageTool unlocks the baseband with BootNeuter 2.0 anyway, at least if you use all the default settings in PwnageTool’s simple mode. Your iPhone’s baseband will be upgraded to 04.05.04_G in the process. Thanks to everyone involved for making this happen! Yee-haw!
By the way: I choose to setup the iPhone as a new iPhone instead of restoring a backup the first time I connected it to iTunes after updating.
Things you may need first: