diff --git a/src/mame/drivers/twin16.c b/src/mame/drivers/twin16.c
index c2ea55db855..1392c16b54b 100644
--- a/src/mame/drivers/twin16.c
+++ b/src/mame/drivers/twin16.c
@@ -304,7 +304,7 @@ static INPUT_PORTS_START( devilw )
 	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_COIN1 )
 	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_COIN2 )
 	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_UNUSED )
-	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_BUTTON4 ) PORT_NAME("Map Button") // advance through tests
+	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_START1 ) PORT_NAME("Map Button") // advance through tests
 	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_UNUSED )
 	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_UNUSED )
 	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_SERVICE1 )
@@ -356,7 +356,7 @@ static INPUT_PORTS_START( darkadv )
 	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_COIN1 )
 	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_COIN2 )
 	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_COIN3 )
-	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_BUTTON4 ) PORT_NAME("Map Button") // advance through tests
+	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_START1 ) PORT_NAME("Map Button") // advance through tests
 	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_UNUSED )
 	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_UNUSED )
 	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_SERVICE1 )