diff --git a/src/mame/drivers/centiped.c b/src/mame/drivers/centiped.c
index db9b560e774..65cb981afaa 100644
--- a/src/mame/drivers/centiped.c
+++ b/src/mame/drivers/centiped.c
@@ -417,18 +417,12 @@ The Two Bit Score "Dux" hack was circulated and common enough for inclusion
     ------------------------------------------
 
 Maze Invaders:
+http://www.atarigames.com/safestuff/mazeinvaders.html
 
 -  The controls are somewhat like Food Fight in the way that they need to be
 'calibrated' as you play or before you start by pushing a couple seconds in
 each direction to assign the boundries.
 
--  The second button makes an audible tone while playing the game but does
-not appear to be used in any capacity in the game.  The prototype cabinet
-(looks like it was made from a Tempest cabinet shell) shows 2 buttons,
-so it is mapped.
-
-http://www.atarigames.com/safestuff/mazeinvaders.html
-
 ***************************************************************************/
 
 #include "emu.h"
@@ -818,7 +812,7 @@ static ADDRESS_MAP_START( mazeinv_map, ADDRESS_SPACE_PROGRAM, 8 )
 	AM_RANGE(0x2500, 0x2502) AM_WRITE(coin_count_w)
 	AM_RANGE(0x2503, 0x2504) AM_WRITE(led_w)
 	AM_RANGE(0x2505, 0x2505) AM_WRITE(input_select_w)
-//  AM_RANGE(0x2506, 0x2507) AM_WRITENOP /* ? */
+	AM_RANGE(0x2506, 0x2506) AM_WRITE(centiped_flip_screen_w) 
 	AM_RANGE(0x2580, 0x2583) AM_WRITE(mazeinv_input_select_w)
 	AM_RANGE(0x2600, 0x2600) AM_WRITE(irq_ack_w)
 	AM_RANGE(0x2680, 0x2680) AM_WRITE(watchdog_reset_w)
@@ -1316,22 +1310,24 @@ static INPUT_PORTS_START( mazeinv )
 	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNKNOWN )
 
 	PORT_START("IN2")
-	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_UNKNOWN )		/* Reacts in test mode */
+	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_BUTTON2 ) PORT_NAME("P1 Reverse")
 	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_UNUSED )
-	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_BUTTON1 )
+	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_BUTTON1 ) PORT_NAME("P1 Fire") 		
 	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_START1 )
-	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_BUTTON2 )
+	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_TILT )		// No Function?
 	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_COIN1 )
 	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_COIN2 )
 	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_COIN3 )
 
 	PORT_START("IN3")
-	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_UNKNOWN )		/* Reacts in test mode */
+	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_BUTTON2 ) PORT_PLAYER(2) PORT_NAME("P1 Reverse")
 	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_UNUSED )
-	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_UNKNOWN )		/* Reacts in test mode */
+	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_BUTTON1 ) PORT_PLAYER(2) PORT_NAME("P2 Fire")
 	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_START2 )
 	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_UNUSED )
-	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_UNKNOWN )		/* Does something, activates a second analog range in test mode */
+	PORT_DIPNAME( 0x20, 0x20, DEF_STR( Cabinet ) )
+	PORT_DIPSETTING( 0x20, DEF_STR( Upright ) )
+	PORT_DIPSETTING( 0x00, DEF_STR( Cocktail ) )
 	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_UNUSED )
 	PORT_SERVICE( 0x80, IP_ACTIVE_LOW )
 
@@ -1383,13 +1379,13 @@ static INPUT_PORTS_START( mazeinv )
 	PORT_BIT( 0xff, 0x7f, IPT_AD_STICK_Y ) PORT_MINMAX(0x40, 0xbf) PORT_SENSITIVITY(100) PORT_KEYDELTA(10) PORT_REVERSE PORT_PLAYER(1)
 
 	PORT_START("STICK1")
-	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )
+	PORT_BIT( 0xff, 0x7f, IPT_AD_STICK_Y ) PORT_MINMAX(0x40, 0xbf) PORT_SENSITIVITY(100) PORT_KEYDELTA(10) PORT_PLAYER(2)
 
 	PORT_START("STICK2")
 	PORT_BIT( 0xff, 0x7f, IPT_AD_STICK_X ) PORT_MINMAX(0x40, 0xbf) PORT_SENSITIVITY(100) PORT_KEYDELTA(10) PORT_PLAYER(1)
 
 	PORT_START("STICK3")
-	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )
+	PORT_BIT( 0xff, 0x7f, IPT_AD_STICK_X ) PORT_MINMAX(0x40, 0xbf) PORT_SENSITIVITY(100) PORT_KEYDELTA(10) PORT_REVERSE PORT_PLAYER(2)
 INPUT_PORTS_END