Complete factory reset after rooting?

[wille95]

I have a few problems in trying to completely recover my Evo. I rooted the phone and did all that was required at the time. Now, I'm giving the phone to somebody else and need to put it back in it's original state pre-root. However, when trying to do a factory reset from either the settings option in the phone or from the HBOOT menu, it does absolutely nothing. I don't know what else to do to clear the device. Any suggestions? Also, could part of the reason be that I removed the SD card that had all of the root data? Thanks in advance!