HTC Eris :: Easy Instructions To Unroot Back To Stock?

I know there are many threads on this already, and I apologize for creating yet another one, but I can't seem to find a clear answer on how to do this. I've already tried the method described in the "Guide from stock 1.5 to the latest root 2.1 thread" and that method failed. Here is the situation, I'm having an issue with my phone that is basically making it unusable, see this thread: Phone stuck in headset mode. This is my 2nd eris after having it replaced once already, and I'm going to try and use this problem as an excuse to complain my way to an upgrade. But before I go into Verizon I need to unroot my phone. I currently have a rooted v of 2.1, I'm not sure what is is called but I think it's basically a rooted version of the official OTA. I am not on Leaked.

Now after the OTA I don't know if 100% stock means 1.5 or 2.1 but basically I need it so Verizon can't see that I've voided my warranty. I am looking for an idiots guide to going back to 100% stock. I've found a few threads on this but I am not tech savy enough to understand the technically discussion to know if these methods will even work for me. I'm looking for a easy to follow guide back to stock that is written so that even an 8 year old can follow it. And I'm not talking about one of those freaky computer genius 8 year old, I'm talking about the kind of 8 year old that picks his nose and eats paste, the one who is a little bit slow. You know who I'm talking about we all went to school with at least one kid like that.