I upgraded my ipod touch 2g to ios 4 in july and since then my use of the device has decreased by about 75%. The wifi won't work on it. I desperately want to get back to ios 3.1.3 where things worked correctly. I didn't save any shsh blobs when i had 3.1.3 installed. However, i do have a backup of my ipod, which was running 3.1.3 stored on my work pc that i recently discovered. Is there any way I can use that backup to get back to 3.1.3?