I have a jailbroken ipod and i did a software update and it turns off and on
it is a piece of trash
If your iPod is jailbroken you shouldn't have done an update thats a #1 rule .
do reset on your computer (plug in your iPod. and in I-tuns click reset iPod)other than that i think it might be trash. Note that you Loose your stuff on your iPod and you will need to re-install all your apps.