diff --git a/src/mame/drivers/viper.cpp b/src/mame/drivers/viper.cpp
index 995dfa411ef..3bd394b92e0 100644
--- a/src/mame/drivers/viper.cpp
+++ b/src/mame/drivers/viper.cpp
@@ -2107,16 +2107,15 @@ static INPUT_PORTS_START( viper )
 	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )
 	
 	PORT_START("IN2")
-	// defaults for Tsurugi, others may differ?
 	PORT_DIPNAME( 0x01, 0x01, "DIP4" ) PORT_DIPLOCATION("SW:4")
 	PORT_DIPSETTING( 0x01, DEF_STR( Off ) )
 	PORT_DIPSETTING( 0x00, DEF_STR( On ) )
 	PORT_DIPNAME( 0x02, 0x02, "DIP3" ) PORT_DIPLOCATION("SW:3")
 	PORT_DIPSETTING( 0x02, DEF_STR( Off ) )
 	PORT_DIPSETTING( 0x00, DEF_STR( On ) )
-	PORT_DIPNAME( 0x04, 0x04, "DIP2" ) PORT_DIPLOCATION("SW:2")
-	PORT_DIPSETTING( 0x04, DEF_STR( Off ) )
-	PORT_DIPSETTING( 0x00, DEF_STR( On ) )
+	PORT_DIPNAME( 0x04, 0x00, DEF_STR( Flip_Screen ) ) PORT_DIPLOCATION("SW:2")
+	PORT_DIPSETTING( 0x04, DEF_STR( Yes ) )
+	PORT_DIPSETTING( 0x00, DEF_STR( No ) )
 	PORT_DIPNAME( 0x08, 0x00, "DIP1" ) PORT_DIPLOCATION("SW:1")
 	PORT_DIPSETTING( 0x08, DEF_STR( Off ) )
 	PORT_DIPSETTING( 0x00, DEF_STR( On ) )