error 21

Good afternoon guys I'm new to arcade projects and hope to help when I can, but for now I have an issue with a chihiro pc in my ghost squad machine that I could use some help with. Error 21 - the game is not acceptable with main board. I have used 2 separate identical disks and 4 different...

Good afternoon everyone. A few days ago I bought a naomi system with dimm firmware 4.02 with CF card, it included the Dolphin blue game, I connected it to my arcade and it worked correctly, I tried to load another game but it didn't work, I downloaded the corresponding roms in the first...