HI there,
I have made great progress with the multiboot.
After hitting the wall multiple times with the different solutions I tried, i finally have one working !
I took inspiration of the KI2 downgrade kit security board.
I will make a video of the complete setup pretty soon, in the mean time find attached some picture of my development setup and 3D renders of the add-on board (looks huge but it's in fact pretty small 3.3cm X 5.3cm (1.3" X 2")).
Three nice features of this solution:
- Can be use on already modded board with lifted EPROM pins (simply connect the wire A19 to the output of this board)
- On power cycling it will boot the last played game
- Reset button will reset to the current game