NES 2.0 Mapper 438
NES 2.0 Mapper 438 denotes the K-3071 multicart circuit board for NROM-128/NROM-256 games with selectable mirroring.
A~[1... .... ..PP PPpN] D~[..CC CCCM]
|| |||| || |||+- Mirroring (0=Vertical, 1=Horizontal)
|| |||| ++-+++-- CHR A17..A13
|| |||+--------------- PRG mode (0=NROM-128, 1=NROM-256)
++-+++---------------- PRG A18..A14