Many people ask, “Why do I have to flash a STOCK/OEM rom before flashing a custom rom?”
The absolute reason is not totally clear to me. However, ALL of the respected chefs on XDA require that you do so before posting a request for help.
The most common problem that I have seen (which was associated with NOT flashing OEM first) was: The phone works well for a while but then it starts doing HARD resets on its own – for no apparent reason. And, a hard reset erases all of your data and configuration – just like when you flash a new OEM/custom rom. And, if that happens a few times, you will WISH that you had taken the extra 5-10 minutes to flash OEM before flashing custom.
ALWAYS flash the appropriate OEM rom for your phone. If you have an ATT Tilt, then use the rom located here. If yours is an HTC-branded device, the the rom here.
For more info about GENERAL flashing procedures, [cref 4 check out this post].
Ray Waldo is a retired pastor with a passion for making technology accessible for the ordinary person. His religious organization has assigned him as the unofficial "Technology Evangelist" for the State of Louisiana. Ray prefers the title "Bishop of Technology."