What Is It?
A discrete logic Nintendo-made board.
Max 128K of PRG ROM, a 74161, and an 8K VRAM.
Note: this board has bus conflicts.
The LS161 acts as a latch. It latches D0 and D1. Writing anywhere in the 8000h-
FFFFh range will set this latch using the above data lines.
7 bit 0
The B bits select a 32K PRG ROM page at 8000-FFFFh.
Mirroring is hardwired on the cart.