Ever upgraded your device to a firmware then you regretted later? This guide can help you resolve the problem. I’ll be downgrading my iPod touch 2G (this works on every device) from iPhone OS 3.1 BETA 7C106c to iPhone OS 3.0 7A341.
First, plug your device into your computer and open iTunes.
If you already have your device’s Restore Image (.ipsw) place it somewhere handy like your Desktop for quick access. If you don’t have it, grab yourself a copy over here.
Restore your device to the old OS (in this case, iPhone OS 3.0). Don’t unplug or do anything to your device during the restore and after unless told to. Let it finish. You will get an error, this is actually good. Don’t unplug or do anything to your device yet.
Note: Mac users, copy the “libusb-0.1.4.dylib” file to “/usr/local/lib/” (Apple + Shift + G) before using the executable.
Extract the zip on your desktop. Put the iRecovery executable on your desktop. Open Terminal (Apple + U). Enter the following: “cd ~/Desktop” *return* “./iRecovery -s” *return* “fsboot” *return* “exit” *return*. You can then close Terminal.
Windows users: Run the libusb installer first then run iRecovery from the iRecovery_SVN folder.
Once you’re done with iRecovery your device is safely restored to iPhone 3.0 (in this example).
WARNING: PLANET-IPHONES.COM NOR THE AUTHOR IS RESPONSIBLE FOR ANY DAMAGE DONE TO THE DEVICE.