I don't remember getting this message with reicast. Does it show when you're launching the game ? Usually, if the ROM/disc image is not correct, you're returned to the game list. Did you try to launch the same game with flycast ?
@tackett1980 Cool.. you know, I'm just gonna say the difference in bios files might be a wild goose chase.. so only search for mine if you're really bored :P Hopefully the reicast folks will address the build issue with the stable branch on rpi3.