you must in the arcade.def file, identify the system 256
{
"id": "cobrata",
"name": "Cobra: The Arcade",
"driver": "sys246",
"dongle":
{
"name": "cbr1verb.ic002"
},
"hdd":
{
"name": "cbr1-ha.chd"
},
"buttons":
{
"3": "circle"
},
"inputMode": "lightgun",
"screenPosXform": [ -65535, 0, 65535, 0 ],
"eeFrequencyScale": [4, 3],
"boot": "ac0:CBRLOAD",
"patches":
[
{
"address": "0x002ECE74",
"value": "0x0",
"description": "Skip card detection"
},
{
"address": "0x002ECF18",
"value": "0x0",
"description": "Skip card detection"
},
{
"address": "0x002ECF58",
"value": "0x1840002E",
"description": "Skip card detection"
}
]
}
just add the line "driver": "sys246", in your arcade.def