WARNING: This will perform a complete wipe, this is the cost of a hard root.
- Click here:
http://forum.xda-developers.com/showthread.php?t=701004
- Follow directions in Section 2
- Download any Stock ROM from here:
http://forum.ppcgeeks.com/showthread.php?t=121961 (I suggest 1.47 ROM to save time updating at the end)
- Copy Stock ROM to SD Card
- Follow directions in Section 3 (download/copy custom recovery)
- Follow directions in Section 4 (but use the Stock ROM instead of the rooted ROM it suggests)
- Stop at Step 34
- After reboot, you should be back on a clean locked stock ROM
- Menu > Settings > System Updates > HTC Software Update
- You should be prompted with the official Froyo ROM update (if not, do a couple of clean reboots and try again)
Hopefully that is easy enough.