Downgrade iPod touch?

Why do i keep getting the error that my ipod touch firmware is not compatible when i try to downgrade it?

• My ipod touch is 3g and it on firmware 4.0. im trying to jailbreak it and in order to do that i need to downgrade it to 3.1.2. or 3.1.3. every time i go into itunes 9.2 to downgrade (shift + restore) it tells me that my firmware is not compatible. i can't seem the find the answer to this anywhere. Any help with be appreciated and ty for your time.

• Answer:

  Apple doesn't really allow anyone to downgrade the OS of the iPod. You'd probably have to find a download somewhere else (it's probably on a torrent site) and even if you managed to find one, you'd have to figure out some way to make iTunes install it on the iPod. Even if you got that far, iTunes would probably detect that you're trying to install an earlier version of the iPod OS, and it might not let you. So in short, just wait for a jailbreak for the OS version you currently have.