[schettj]

Yep, it is.

HTC devices have *2* firmwares (roms) that can be updated more or less separately

The Radio firmware (usually shortened to "radio" here) is the firmware just for the radio itself. Usually any number of radio firmware versions will work, and have slightly different tweaks. Generally but not always the most recent is the best.

The ROM is the other firmware - it's got the operating system, and any pre-installed apps "cooked in" (hence the talk of chefs, kitchens, etc around here as well) and is usually just shortened to 'ROM' around here.

Some roms will need or work best with specific radios, and if so they will specify which radio you need... that means you need to flash that radio firmware.

Sometimes but not always, you can flash a new radio firmware without 'hard resetting' - or wiping out all your data on the phone. You always hard reset after a ROM flash.

Make sense?

Edit: When you get an OEM 'rom update' - ie, from Sprint or Verizon - it will usually update BOTH the radio and the OS roms. Custom ROMs usually do NOT update the radio, so you have to do that in a separate step before flashing the custom rom.