So, I downloaded 2.1 ESE53...

[DaveTheRealtor]

I downloaded 2.1 ESE53 from HERE. Do I really need to root or can I just rename it to update.zip?

 

[GivenToFly]

you need to be rooted, just renaming it to update won't load it. I believe the rom is setup as a recovery image which they have you load through terminal.