Root need help getting rid of the unofficial 2.2 update for the epic and getting the stock 2.1 back on it

[vweezy]

Ok so I installed the 2.2 update for the epic thinking it was the final version... found out it wasn't the official update now I'm trying to get rid of it and go back to stock... will I need to root my phone in order to do that? And how would I go back to stock?

 

[Damar1979]

Try to use odin to revert back to stock

 

[larryrenn]

I did the unofficial update to 2.2 and honestly i dont like it. I have tried reading posts about how to go back but im stuck. Can i just havr a simple explanation on how to root back and where exactly is this odin file and what to you do with it