NES 2.0 Mapper 434

NES 2.0 Mapper 434 denotes the S-009 PCB, used by multicarts consisting of several UNROM games.

Outer Bank Register ($6000-$7FFF)

Mask: $E000

D~7654 3210
  ---------
  ..M. .PPP
    |   +++- PRG A19..A17
    +------- 0: Horizontal mirroring
             1: Vertical mirroring

Inner Bank Register ($8000-$FFFF)

Mask: $8000

D~7654 3210 (bus conflicts)
  ---------
  .... .PPP
        +++- PRG A16..A14 if CPU A14=0