Redirect MMIO requests to another address

Question

I'm trying to modify GBA/NDS games so that they can be programmatically controlled, via a controller over a network.

Games read input via the read-only 0x4000130 device register. Is there anyway to reroute reads to this address to another address? The other address would be R/W and store input from the controller.

Specifically, the GBA/NDS are bare metal embedded devices, so I'm not too sure if this is even possible. Would I need to somehow redirect addresses within the address bus for this specific address? Is a BIOS modification needed to allow such redirection?

Answer 1

Apart from modifying the game code so that it reads from a different location, it's simply not possible. You may have more success modifying the hardware. For example, you could rewire the buttons to a Raspberry Pi, so that the Pi can make the circuit think the button is pressed.