I have an old Iphone purchased last year. I download PWNAGE Tools, followed all the steps and got to the end where it created the .ipsw file.
It never asked me to install the bootloader file that it states on the step by step account at the modmyi website.
At the end i restored my iphone clicked option and then restore and restored the modified file created by PWNAGE and after a minute itunes came up with an error telling me i couldnt restore it
I have just had exactly the same problem. I did everything according to the instructions but Pwnage started building the custom restore software without asking for the Bootloader files. When I tried to restore in iTunes, it said it was unable due an "unknown error ~1600", or something similar.
I was trying to restore to 2.0.1 the first time. I re-tried using firmware 2.0 but still got the same error message.
I still get error 1600 to this day after updating my OSX to 10.5.5. I've tried a fresh restore of iTunes... I've tried manually re-installing the update. I've re-installed pwnage... created new firmwares... etc etc with no avail. I have to resort to quickpwn and then connect to wifi and download bootneuter to unlock.