[tx_dbs_tx]

You definitely need to unroot your EVO and then flash the stock Sprint ruu. If you rooted with unrevoked then you need to run the unrevoked "hboot S-On" tool FIRST, before flashing back to stock Rom. The hboot S-On tool is a .zip file and you run it the same way you flash a custom Rom. The tool can be found here in the forum and on unrevoked's website.

You're right, dont give Sprint a reason to void your 1 year warranty by returning 6our EVO without putting it back to original stock condition. It's not worth the risk. I got my new EVO in 2 days.