NES 2.0 Mapper 328
NES 2.0 mapper 328 is used for the Test Ver. 1.01 Dlya Proverki TV Pristavok test cartridge. Its UNIF board name is UNL-RT-01. There is only 16K of PRG and 2K of CHR and mirroring is hard-wired.
Random number generator or Protection ($CE80-$CEFF, $FE80-$FEFF, read)
Mask: unknown. If what CaH4e3 wrote (quoted below) is accurate, $BFFF. D~7654 3210 --------- 1111 RR1R ++-+- Random bits
CaH4e3 wrote that the "PRG EPROM has copy protected areas with "weak bits", which is tested at some points of the program. [The random numbers are t]rying to simulate "weak bits" behaviour"
The relevant program calculates a 16-bit checksum of the memory in each of these regions and loops until the checksum changes.