What is a bad dump?
A bad dump is a ROM image that is incorrect for some reason. There are numerous reasons that bad dumps occur; partially dumping a ROM (only half of it for example), incorrectly connecting it up for dumping, a faulty/damaged ROM, etc. Bad dumps are often discovered when someone first tries to emulate the game or when someone else dumps the same game and finds the two dumps don’t match. Another time that bad dumps are discovered is when a new clone is dumped and after comparing the ROMs in both games it is realised that one of the original dumps was bad. Once a dump is discovered to be bad, the bad CRC in MAME will be replaced with the new good CRC.
