Frustration with downgrading iPod From 4.2.1 to 3.1.3

[LiquidSolstice]

So, keep in mind, I'm doing this over the phone/through instant messaging/TeamViewer.

My girlfriend's been complaining to me that the iPod Touch I bought her (2nd Gen 8GB Non-MC Model) has had completely shot battery life since upgrading from her jailbroken iOS 3.1.3 to 4.2.1. We've narrowed it down to the wifi, for some reason, the wifi power save settings have become absolutely retarded on her Touch, and has been sapping the battery to the point where it's unusable because it always seems to be dying or is dead.

I want to put her back on 3.1.3, so I followed the usual guide; editing her hosts file to block the Apple restore check, putting iPod in DFU, holding shift while pressing restore to pick the original 3.1.3 IPSW, and I keep ending with this super frustrating 1394 Error, which is apparently the "failed to verify restore" error.

Any ideas what's going on? I've heard of some app called TinyUmbrella, or something like that, which is supposed to help, but I'm not sure how it works. I just really need her Touch working, she depends on it a lot while on the go since her campus has total campus wifi coverage.

If all else fails, I plan on jailbreaking her current 4.2.1 and just installing SB Settings (she's used to it, and knows how it works) and she'll have to deal with the inconvenience of having to turn the wifi on and off.

[Freelancer1111]

TinyUmbrella is to store the SHSH of your iPod. These are unique files to verify your Firmware.

If you didn't store them before upgrading, i think there is no way to downgrade.

[NoLiMiT06]

There is no way to downgrad unless you did what the post above me says, I have a 2g mc model and it works like it brand new with great battery life.

[Xenomorph]

To further expand:

- Each time you install an OS on your device, iTunes will verify (ask permission) the install with Apple.

- Apple is ONLY giving permission to install 4.2.1 right now. All attempts to install 4.1, 4.0, 3.1.x, etc will fail if you ask Apple.

- TinyUmbrella is used to backup the "permission" Apple gives your device. So if you backed up the "permission" (in the form of SHSH, a Secure Hash / signature), you can then use TinyUmbrella to fool iTunes into thinking Apple is giving you permission to install 3.1.3 or whatever.

So .. did you back up your SHSH?