Tested. The board seems to work with a single game. However, the multi game function may not work properly depending on which games you use because of how the Genesis hardware works.

This is a modified HD Retrovision cart.

This can be used as a basic Genesis cart with a max ROM size of 8Mib. Or with the 74161 installed, you can use this as a 2-in-1 or 4-in-1 multi cart (combined ROMs can be a max of 8Mib). Games are switched by console reset button. The multi game function did not work with my testing.

There are jumpers for the A18 and A17 address lines that will have to be set depending on how many games will be on the cart and what size memory you are using. For either jumper, closing positions 1 and 2 will allow the console to control that address line. Closing positions 2 and 3 will allow the 161 to control that address line. View the tables below to see how to set the jumpers when using 29F800 or 29F400 memory.

Memory = 29F800

Memory = 29F400

BOM:

*If you are only installing one game on the cart, leave U2 and C3 unpopulated.

**Jumper pads are spaced for 0 ohm 0805 resistors, but they are not necessary. You can simply use a blob or solder, or a bit of wire, or the trimmed legs from C1.

LED is 1206 package to make it easy if you wish to use a through hole LED instead of surface mount (it has the benefit of standing tall in the cart shell).