These are instructions on how to downgrade your original iPhone from 2.0 to 1.1.4.
You will have to perform this tutorial if you accidentally updated to the 2.0 firmware or you just rather be on 1.1.4.
If you have Windows, uninstall iTunes 7.7 and then reboot your computer.
If you have Mac OS X, open Terminal from Applications:Utilities. Enter the following commands into the Terminal window:
defaults write com.apple.iTunes StoreActivationMode -boolean NO
defaults write com.apple.iTunes StoreGeniusMode -boolean NO
rm -r /Applications/iTunes.app
rm -r /Library/Receipts/iTunesX.pkg
Install iTunes 7.5 onto your computer using the download links.
Before attempting to launch iTunes 7.5 for the first time you need to delete or rename the iTunes folder.
Rename the C:Documents and Settings**your user name**My DocumentsMy MusiciTunes folder to iTunes Backup.
Put your iPhone into DFU mode by following these instructions.
If you get an error in the 1600s then try putting the iPhone into DFU mode and try again. You might also want to try a different USB port and restart your system and if all else fails use a different computer!
Now you can use your favourite unlocking method to kick your iPhone out of restore mode and unlock it.