NES 2.0 Mapper 378 denotes a circuit board with unknown ID, used for an 8-in-1 512 KiB multicart containing one AxROM and two UNROM games.
Mask: $8000
A~FEDC BA98 7654 3210
-------------------
1... .... ..MS cbaa
|| |+++- PRG A15-A17
|| |+--- UNROM only: 0=Vertical, 1=Horizontal mirroring
|| +---- UNROM only: PRG A14 when CPU A14=0
|+------ CIRAM A10 in AxROM mode
+------- PRG A18, also:
0: AxROM mode: PRG A14=CPU A14
1: UNROM mode: PRG A14=c if CPU A14=0,
PRG A14..16=7 if CPU A14=1
Categories: Mappers with CHR RAM, Multicart mappers