Quoted from slochar:
More Black Hole bugs..... really, system 80 bugs. If you have larger game roms the OS never tests rom 2. If there's an error in rom 1 but in the upper half of it, it reports it as rom2 bad, when in fact, it's still rom 1. (basically any game after Counterforce never checks the range $1400-$17FF, so you could have a bad gamerom 2 and the game will not report it)
Kind of a large oversight, but while the OS can expand in some ways, they really didn't design it out of the box for this. System 80a corrects this.
and thats why you don't solder your roms to your damn boards...