NES 2.0 Mapper 288

NES 2.0 Mapper 288 is used for two GKCX1 21-in-1 multicarts. Oddly, GoodNES 3.23b has them set to INES Mapper 133 even though it is entirely incompatible with that mapper.

Address latch

A~1... .... ...P PCCC
               | |+++- Select 8 KiB CHR-ROM bank at PPU $0000-$1FFF
               +-+---- Select 32 KiB CHR-ROM bank at CPU $8000-$FFFF

Mirroring seems to be hard-wired to vertical for all known images.