Some work towards Aqua Stage, looks like both SH-2/SH-1 shared RAMs addresses can be modified somehow. It currently asks for attendant if out of service mode (which is probably the purpose of the extra input field I suppose). (nw)

src/mame/drivers/coolridr.c

@@ -2856,6 +2856,12 @@ static ADDRESS_MAP_START( system_h1_map, AS_PROGRAM, 32, coolridr_state )
 	AM_RANGE(0x60000000, 0x600003ff) AM_WRITENOP
 ADDRESS_MAP_END
 
+static ADDRESS_MAP_START(aquastge_h1_map, AS_PROGRAM, 32, coolridr_state)
+	AM_RANGE(0x03c00000, 0x03c0ffff) AM_MIRROR(0x00200000) AM_RAM_WRITE(sysh1_dma_w) AM_SHARE("fb_vram") /* mostly mapped at 0x03e00000 */
+	AM_RANGE(0x03e10000, 0x03e1ffff) AM_RAM AM_SHARE("share3") /*Communication area RAM*/
+	AM_RANGE(0x03f00000, 0x03f0ffff) AM_RAM AM_SHARE("share3") /*Communication area RAM*/
+	AM_IMPORT_FROM(system_h1_map)
+ADDRESS_MAP_END
 
 READ16_MEMBER( coolridr_state::h1_soundram_r)
 {
@@ -3034,6 +3040,15 @@ static ADDRESS_MAP_START( coolridr_submap, AS_PROGRAM, 32, coolridr_state )
 	AM_RANGE(0x60000000, 0x600003ff) AM_WRITENOP
 ADDRESS_MAP_END
 
+static ADDRESS_MAP_START( aquastge_submap, AS_PROGRAM, 32, coolridr_state )
+	AM_RANGE(0x05210000, 0x0521ffff) AM_RAM AM_SHARE("share3") /*Communication area RAM*/
+	AM_RANGE(0x05200000, 0x0537ffff) AM_RAM
+	AM_RANGE(0x06000200, 0x06000207) AM_WRITENOP // program bug?
+	AM_RANGE(0x06100018, 0x0610001b) AM_READ_PORT("IN7")
+	
+	AM_IMPORT_FROM(coolridr_submap)
+ADDRESS_MAP_END
+
 /* TODO: what is this for, volume mixing? MIDI? */
 WRITE8_MEMBER(coolridr_state::sound_to_sh1_w)
 {
@@ -3057,6 +3072,134 @@ static GFXDECODE_START( coolridr )
 //  GFXDECODE_ENTRY( NULL, 0, tiles16x16_layout, 0, 0x100 )
 GFXDECODE_END
 
+#define DUMMY_INPUT_PORT(_x_) \
+	PORT_START(_x_) \
+	PORT_DIPNAME( 0x00000001, 0x00000001, _x_ ) \
+	PORT_DIPSETTING(    0x00000001, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00000002, 0x00000002, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00000002, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00000004, 0x00000004, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00000004, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00000008, 0x00000008, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00000008, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00000010, 0x00000010, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00000010, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00000020, 0x00000020, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00000020, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00000040, 0x00000040, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00000040, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00000080, 0x00000080, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00000080, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00010000, 0x00010000, _x_ ) \
+	PORT_DIPSETTING(    0x00010000, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00020000, 0x00020000, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00020000, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00040000, 0x00040000, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00040000, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00080000, 0x00080000, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00080000, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00100000, 0x00100000, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00100000, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00200000, 0x00200000, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00200000, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00400000, 0x00400000, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00400000, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_DIPNAME( 0x00800000, 0x00800000, DEF_STR( Unknown ) ) \
+	PORT_DIPSETTING(    0x00800000, DEF_STR( Off ) ) \
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) \
+	PORT_BIT( 0xff00ff00, IP_ACTIVE_LOW, IPT_UNUSED ) \
+
+static INPUT_PORTS_START( aquastge )
+	DUMMY_INPUT_PORT("IN0")
+
+	PORT_START("IN1")
+	PORT_DIPNAME( 0x00000001, 0x00000001, "IN1" ) 
+	PORT_DIPSETTING(    0x00000001, DEF_STR( Off ) ) 
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) 
+	PORT_DIPNAME( 0x00000002, 0x00000002, DEF_STR( Unknown ) ) 
+	PORT_DIPSETTING(    0x00000002, DEF_STR( Off ) ) 
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) 
+	PORT_DIPNAME( 0x00000004, 0x00000004, DEF_STR( Unknown ) ) 
+	PORT_DIPSETTING(    0x00000004, DEF_STR( Off ) ) 
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) 
+	PORT_DIPNAME( 0x00000008, 0x00000008, DEF_STR( Unknown ) ) 
+	PORT_DIPSETTING(    0x00000008, DEF_STR( Off ) ) 
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) 
+	PORT_BIT( 0x00000010, IP_ACTIVE_LOW, IPT_JOYSTICK_DOWN ) PORT_PLAYER(1) 
+	PORT_BIT( 0x00000020, IP_ACTIVE_LOW, IPT_JOYSTICK_UP ) PORT_PLAYER(1) 
+	PORT_DIPNAME( 0x00000040, 0x00000040, DEF_STR( Unknown ) ) 
+	PORT_DIPSETTING(    0x00000040, DEF_STR( Off ) ) 
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) 
+	PORT_DIPNAME( 0x00000080, 0x00000080, DEF_STR( Unknown ) ) 
+	PORT_DIPSETTING(    0x00000080, DEF_STR( Off ) ) 
+	PORT_DIPSETTING(    0x00000000, DEF_STR( On ) ) 
+	PORT_BIT( 0x00010000, IP_ACTIVE_LOW, IPT_COIN1 ) PORT_NAME("P1 Coin")
+	PORT_BIT( 0x00020000, IP_ACTIVE_LOW, IPT_COIN2 ) PORT_NAME("P2 Coin")
+	PORT_SERVICE_NO_TOGGLE( 0x00040000, IP_ACTIVE_LOW )
+	PORT_BIT( 0x00080000, IP_ACTIVE_LOW, IPT_SERVICE1 ) PORT_NAME("P1 Service Switch")
+	PORT_BIT( 0x00100000, IP_ACTIVE_LOW, IPT_START1 ) PORT_NAME("P1 Start")
+	PORT_BIT( 0x00200000, IP_ACTIVE_LOW, IPT_START2 ) PORT_NAME("P2 Start")
+	PORT_BIT( 0x00400000, IP_ACTIVE_LOW, IPT_SERVICE2 ) PORT_NAME("P2 Service Switch")
+	PORT_BIT( 0x00800000, IP_ACTIVE_LOW, IPT_UNUSED )
+	PORT_BIT( 0xff00ff00, IP_ACTIVE_LOW, IPT_UNUSED ) 
+	
+	DUMMY_INPUT_PORT("IN2")
+
+	DUMMY_INPUT_PORT("IN3")
+
+	DUMMY_INPUT_PORT("IN5")
+
+	DUMMY_INPUT_PORT("IN6")
+
+	DUMMY_INPUT_PORT("IN7")
+
+	PORT_START("AN0")
+	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )
+
+	PORT_START("AN1")
+	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )
+
+	PORT_START("AN2")
+	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )
+
+	PORT_START("AN3")
+	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )
+
+	PORT_START("AN4")
+	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )
+
+	PORT_START("AN5")
+	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )
+
+	PORT_START("AN6")
+	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )
+
+	PORT_START("AN7")
+	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )
+
+
+	// driver debug
+	PORT_START("CONFIG")
+	PORT_CONFNAME( 0x01, 0x01, "Use Threading Code" )
+	PORT_DIPSETTING(    0x00, DEF_STR( Off ) )
+	PORT_DIPSETTING(    0x01, DEF_STR( On ) )
+INPUT_PORTS_END
+
 static INPUT_PORTS_START( coolridr )
 	PORT_START("IN0")
 	PORT_DIPNAME( 0x00000001, 0x00000001, "IN0-0" )
@@ -3623,6 +3766,14 @@ static MACHINE_CONFIG_START( coolridr, coolridr_state )
 	MCFG_SOUND_ROUTE(0, "rspeaker", 1.0)
 MACHINE_CONFIG_END
 
+static MACHINE_CONFIG_DERIVED( aquastge, coolridr )
+	MCFG_CPU_MODIFY("maincpu")
+	MCFG_CPU_PROGRAM_MAP(aquastge_h1_map)
+
+	MCFG_CPU_MODIFY("sub")
+	MCFG_CPU_PROGRAM_MAP(aquastge_submap)
+MACHINE_CONFIG_END
+
 ROM_START( coolridr )
 	ROM_REGION( 0x200000, "maincpu", 0 ) /* SH2 code */
 	ROM_LOAD32_WORD_SWAP( "ep17659.30", 0x0000000, 0x080000, CRC(473027b0) SHA1(acaa212869dd79550235171b9f054e82750f74c3) )
@@ -3797,5 +3948,5 @@ DRIVER_INIT_MEMBER(coolridr_state, aquastge)
 }
 
 GAME( 1995, coolridr,    0, coolridr,    coolridr, coolridr_state,    coolridr, ROT0,  "Sega", "Cool Riders",GAME_IMPERFECT_SOUND) // region is set in test mode, this set is for Japan, USA and Export (all regions)
-GAME( 1995, aquastge,    0, coolridr,    coolridr, coolridr_state,    aquastge, ROT0,  "Sega", "Aqua Stage",GAME_NOT_WORKING)
+GAME( 1995, aquastge,    0, aquastge,    aquastge, coolridr_state,    aquastge, ROT0,  "Sega", "Aqua Stage",GAME_NOT_WORKING)