[dole]

ROMs are a group of files needed to run the phone. They may be "stock," as a regular phone would come from a carrier like Sprint or AT&T, or "custom," where someone has removed and added some programs and features to improve performance and functionality. Many custom ROMS, for example, remove all traces of the "Sprint" branding (such as the Sprint logo on the TF3D Home screen, and removes the "Sprint" text from the "Sprint Music" tab), and removes the Sprint TV program to free up space on the phone's internal storage memory. These custom ROMs often include a number of performance and visual tweaks (or "reg hacks").

"Flashing" refers to when you write one of these ROMs to your phone, replacing the current one. It's usually called "flashing" as opposed to "writing," because it's being written to a substantial hardware chip, instead of to a drive, or memory card.