MB-91 A

Board

Tech Specs:

Max. 32K PRG ROM.
Max. 32K CHR ROM.
74LS138
74LS175
MX8018-0002-A lockout replacement

Description:

Seems to be an earlier revision of the NINA-03 board. Appears to have some small changes in regard to the lockout defeat.

There is only one register on this cart. It maps in kinda strangely.

4100-41FF, 4300-43FF, 4500-45FF ... 5F00-5FFF

7       0
---------
xxxx xxCC

C: Selects an 8K CHR ROM bank

CHR banks are unknown on startup.  Mirroring is hardwired on cart.