Is GPROM a typo here? Short for Game PROM maybe?
It's an EPROM, but it's specifically called GPROM at this position. GTB also uses the terms YPROM, DROM, AROM, (these 3 for sound ROMs) and DSROM (for display ROM).
And yes, it is short for game PROM. --Jimpal (talk) 16:03, 30 June 2013 (CDT)