NES 2.0 Mapper 283
From Nesdev wiki
NES 2.0 Mapper 283 is used for the Block Family 6-in-1/7-in-1 multicarts. Its UNIF board name is BMC-GS-2004 (additional 8 KiB PRG-ROM chip present) and BMC-GS-2013 (no additional 8 KiB PRG-ROM chip present).
- CPU $6000-$7FFF: 8 KiB PRG-ROM bank, fixed to last 8 KiB bank within the first 256 KiB block, or if present, to the content of an additional 8 KiB PRG-ROM chip.
- CPU $8000-$FFFF: 32 KiB switchable PRG-ROM bank.
- PPU $0000-$1FFF: 8 KiB of CHR-RAM.
- CPU $8000-$FFFF: Select 32 KiB PRG-ROM bank at CPU $8000-$FFFF.
- Mirroring is fixed and denoted in the NES header.
- The 8 KiB PRG-ROM chip is present and located in the very last PRG-ROM bank if the number of PRG-ROM banks is a power of two plus one. Its data is repeated once since the iNES format only allows for 16 KiB PRG-ROM banks.