I was running a jailbroken 1.1.4 phone, went through the pwnage process, and resulted in a "please connect to itunes" screen on my phone, as opposed to the bootloader screen I expected.
Now I wound up restoring to 2.0, and I cannot downgrade to 1.1.4 or any other firmware and get an error when I try. The phone isn't showing up as activated even though I'm paying for service atm, I don't want to reactivate it again and enter in more payment information when it's already active!!
Try running pwnage again with 2.0 on the iphone. It should still work. Otherwise, there is a guide to downgrading to 1.1.4 that involves downgrading your iTunes also.
put the phone in DFU mode (search google on how to, or use ZiPhone to) and connect to the computer. iTunes will open and hold down shift (or option in mac) while you click restore. Find the PWNED 2.0 ISPW file and it will overwrite everything on your phone with the pwned 2.0.