Can you unupgrade your itouch after you upgrade it?

Yes, go on google and search up iPod touch (1,2,3) generation software download the desired software then put it somewhere you can find it on your desktop I recommend then go into iTunes go to your iPod and hold the shift key on your keyboard and click restore a window will pop up letting you choose a file from your computer and then you choose the previously downloaded file. Hope this helps you :)