Hi, I'm new to the forum and I was helping my friend jailbreak her itouch. Her itouch is 2nd Gen MB model which started with 2.x.x firmware. I tried to make it 4.0 in the beginning and it failed, prompting me to restore. After the restore, the itouch became 4.1 firmware. In order to bring it down to 4.0 you need to first edit your host which is located under your C:\windows\system32\etc\hosts. You edit it by using Notepad. Once you open hosts, add the following onto the bottom (including # and hit TAB key once): 126.96.36.199 gs.apple.com. Once you have done that, put your itouch into recovery mode. To do so, you turn off your itouch without the USB plugged in. Hold on to the home button and plug in the USB, which will bring you to recovery mode. Now hit shift + click restore and select 4.0 firmware for itouch 2g. When everything is finished, connect to Wi-fi and go to jailbreakme.com and your all set. link to firmware: http://www.felixbruns.de/iPod/firmware/ Note: I only did this once and I can't guarantee it to work. Try at your own risk. Hope I helped!