iPad Need help.. How do I update to iOS 5.1 or 5.1.1 on jail broken iPad 1

[Sirpeach]

or a few apps I have come across it tell me I require iOS 5.1 mostly new ones.. I have jail broken iPad 1 .. Can I update or even unjailbrake my iPad. Please help thank you

 

[Kyotoma]

Plug it into your computer, enter DFUmode, then hit restore.