According to the iPhone devs they say this:
So, can I only use QuickPwn or can I make a custom firmware and do a RESTORE in iTunes with the custom firmware? Will iTunes accept it?iPhone 2G (1st Generation)
Update or Restore your iPhone 2G with iTunes then run QuickPwn to do the magic, ‘nuff said, you don’t need to worry about anything.
I updated it directly in iTunes and it's now running 2.2, but one day I may need to restore it. I don't want to use QuickPwn because it's got that pineapple logo... I just want everything standard, no installer, no cydia... this is why I prefer using PwnageTool.