Hey Guys!
i'm posting this here, but actually, I'm not sure if it was supposed to be here, or on the iOs 4, or Iphone 4, or Redsn0w... but anyway.

Here it goes a freaking huge and strange problem, I really hope you guys can help me :/

So, I Jailbroke my Ipod (touch, 4g) a long while ago. But back, on that time, I think I made some mistakes before finally getting it. One of them made my Ipod become useless and dead, hahah. I could not anymore jailbreak it, although I could put it into DFU mode, and I could not restore it normally. So what I had to do was put my Ipod onto DFU, and then restore (the DFU restore - usually, the last hope). So, some time agora, hwne the iOS 5.1 was released, I tried to use the shift + restore to put the version 5.0.1 (which has the unthetered jailbreak), and I got a lot of error messages (error 20, If I'm not mistaking again), aaaaand... it was useless again. But this time, what actually helped me was to jailbreak it again (?) via RedSnow... And then, it was back to the iOs 4.2 (or something), and jailbroken. Ok... I gave up installing the new version... I continued using my Ipod normally. BUT, for some reason, on the last days, it has'n been being able to sync again (?), I mean, Itunes recognizes it, and start to backup and to determine what is going to be sync, but then, it just finishes the sync without sync anything. I don't get any error message, or anything like this...
So, I tried to restore it again... Normal restore (which leads me to the error 20), and the DFU restore (which leads me to the error 1600). Then, my ipod dies, and I have to jailbreak it again (?), and then it is back again. But it's not sync yet, etc.

Does someone can enlighten me, please? Is there any software that completely formats the Ipod, or something...? Or any other method I don't know? Cause actually, I really think that this is because the OS may be corrupted or something, so, although it works, when iTunes try to read it, or something, it's not working.... I don't know, please help me!

and Thank you, in advance (: