I have an interesting problem.
I'm trying to downgrade my ipod touch 2G from 4.0 to any version of 3.
I've tried downgrading to 3.1.2 and 3.1.3, but since it isn't signed by apple anymore, I cannot do that. I don't know if I have the SHSH from cydia to do this...I did have my ipod jailbroken when it was on 2 and 3.1 but I don't know if I can access those files.

So I've been trying to downgrade to 3.0
The problem is this: during the restore process, itunes says it's preparing the device for restore, my ipod gets itself out of DFU mode and boots up to its regular 4.0 OS, with all my aps and info there. I've tried several times and the same exact thing happens every time. Eventually I get a 1601 or a 1602 error. I have no idea what to do at this point, or how to keep it in DFU mode through the restore process.