Yeah, stupid question, how do I do it? Can't figure out any way that seems to work.
I'm trying to get it to 3.1.3, I have a 2G. 4.0 is just too slow for some reason, and it's not what I expected, and I don't want to wait for a jailbreak.
Thanks.
It took me a while to figure out why it wasn't possible. Apparently, it can't be done using firmware 3.1.3. You can only downgrade to firmware 3.1.2.
1) Put your iPod 2G into DFU mode. You do this by holding the power button and the home button until your display turns off. Then release the power button, but keep holding the home button.
If your iPod is plugged in, itunes will then beep and tell you that your iPod is in recovery mode.
2) From there, you need to get the iPod touch 2G 3.1.2 firmware. Search for that, it's easy to find.
3) In iTunes, Option + Click on [Restore] (Mac); Shift + Click on [Restore] (PC). Select the 3.1.2 firmware.
That should do it. One thing I had done, that may make a difference, though I don't think so, is blocking the apple server so that you might be able to get the update past. If the above steps don't work, do this in addition to them:
4) Open up terminal and type: "cd /etc" followed by "sudo vi hosts".
5) Your hosts file will now open up in terminal. Type the letter i so that you can then edit the hosts file. Navigate to the bottom of the file with your arrow keys. On a new line in the file, type: "74.208.10.249 gs.apple.com" (without quotes).
6) Press Escape, followed by Shift + Z + Z.
Good luck. Apple really dumped us iPod Touch users in a ditch with iOS4, because it's some of the most laggy garbage I've ever used.