(adsbygoogle = window.adsbygoogle || []).push({}); settings>general>reset>Erase all content and settings

does this update you to the latest firmware? because i want to get rid of my jailbreak but stay on 5.0.1

DONT DO IT if your jailbroken it doesnt work if your jailbroken it just messes your idevice up i did it to my iphone and it didnt work for 3 days had to take it all apart and disconnect and reconnect all the ribbon cables

I wouldn't recommend it. For me, it took hours and I got the feeling something went wrong.

If you feel you must, turn Airplane mode ON incase there is an auto update feature in iOS 5 (I doubt there is but it pays to be sure )