procedure to update us dvd to work with eu rns-e unit?

Thanks to Proxus for posting the retrofit basics section.What a great job of making the logic of the process understandable from start to finish. I am still confused as to how to update the firmware and modify the us dvd to work with the eu unit. I searched the fourm but was unable to find a comprehensive answer. Can anyone explain the process of updating the firmware and modifying the dvd. I do have good basic computer understanding. :?