Which ROM bricked your Mogul? Sometimes ROM flashes won't let your phone boot, making it appear to be bricked, but you're able go get into bootloader mode to flash a new ROM. If you've flashed your phone and it stops doing anything, except for a red charging light when it's plugged in, then it's really bricked. I have only ever seen this situation come about when flashing a new radio to a phone. My best tips for avoiding bricking your phone are:
1. Never flash a standalone radio. Only install new radios as parts of OFFICIAL HTC upgrades.
2. Never downgrade your radio
3. Never mismatch a new unocker with an old radio (for example: OliPro 1.20 with a GPS radio or OliPro 2.40 without a GPS radio [Mogul example])