If you’re just rooted, everything else is stock (no antenna update, roms,
etc), you’re all set – just follow the direction to apply Forever (
http://unrevoked.com/rootwiki/doku.php/public/forever).

If you’ve updated the antenna, you’ll have to use the RUU method. Use this
guide here:
http://androidforums.com/incredible-all-things-root/123816-how-revert-back-earlier-version-hboot.htmlIf
you have a custom ROM you’ll need to use a nandroid backup to return
to
stock.