NES 2.0 Mapper 344

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NES 2.0 Mapper 344 is used for the Kuai Da Jin Ka Zhong Ji Tiao Zhan 3-in-1 (3-in-1,6-in-1,Unl) multicart. Its UNIF board name is BMC-GN-26.

Outer Bank and Mode Register ($6000-$7FFF, write)

Mask: $E000

A~FEDC BA98 7654 3210
  .... .... .... DMCC
                 ||++- Select PRG and CHR base offsets
                 ||     0: PRG: $00000, CHR: $00000 (Menu/Street Fighter IV)
                 ||     1: Invalid
                 ||     2: PRG: $20000, CHR: $40000 (Contra Force)
                 ||     3: PRG: $40000, CHR: $60000 (Guevara)
                 |+--- Select PRG-ROM mode
                 |      0: Normal MMC3 mode
                 |      1: MMC3 bank register 6 selects 32 KiB
                 |         PRG-ROM bank at CPU $8000-$FFFF
                 +---- 1=CPU $8000-$FFFF becomes open bus if jumper
                         not set (chooses between 3-in-1/6-in-1 menu)

As it uses the MMC3 clones's WRAM interface, writing to the Outer Bank register requires enabling and not write-protecting WRAM in the MMC's $A001 register.

MMC3-compatible registers

Mask: $E001

See MMC3.


  • The inner PRG-ROM bank is restricted to 128 KiB, the CHR-ROM bank unrestricted.
  • This description is based on testing with Nestopia Plus!, which ignores the written data.