bus/nes: Added support for a Big Nose 2-in-1 cart.

- Demoted bignfo to unsupported. It has timing issues like many Camerica games. It is likewise not working in the added 2-in-1.

New working software list additions (nes.xml)
-----------------------------------
2 in 1 - Big Nose the Caveman & Big Nose Freaks Out [MLX]

hash/nes.xml

@@ -4201,7 +4201,7 @@ license:CC0
 		</part>
 	</software>
 
-	<software name="bignfo">
+	<software name="bignfo" supported="no">
 		<description>Big Nose Freaks Out (USA)</description>
 		<year>1992</year>
 		<publisher>Camerica</publisher>
@@ -61302,6 +61302,24 @@ preliminary proto for the PAL version, still running on NTSC systems) or the gfx
 
 <!-- OTHER TAIWANESE ~ CHINESE ~ ASIAN PIRATES-->
 
+	<software name="2bignose" supported="partial">
+		<description>2 in 1 - Big Nose the Caveman &amp; Big Nose Freaks Out</description>
+		<year>199?</year>
+		<publisher>&lt;pirate&gt;</publisher>
+		<info name="serial" value="BC-019"/>
+		<info name="usage" value="Press reset to switch games."/>
+		<part name="cart" interface="nes_cart">
+			<feature name="slot" value="kn42" />
+			<feature name="mirroring" value="vertical" />
+			<dataarea name="prg" size="524288">
+				<rom name="2-in-1 high standard game (bc-019).prg" size="524288" crc="330623a4" sha1="ad189495ed8b6d60dddcbb970be17174b2389e63" status="baddump" />
+			</dataarea>
+			<!-- 8k VRAM on cartridge -->
+			<dataarea name="vram" size="8192">
+			</dataarea>
+		</part>
+	</software>
+
 	<software name="2dkjb" supported="no">
 		<description>2 in 1 - Donkey Kong &amp; Jungle Book</description>
 		<year>19??</year>
@@ -78732,6 +78750,7 @@ be better to redump them properly. -->
 		<description>4 in 1 (Alt 2)</description>
 		<year>19??</year>
 		<publisher>&lt;pirate&gt;</publisher>
+		<info name="usage" value="Press reset to switch games."/>
 		<part name="cart" interface="nes_cart">
 			<feature name="slot" value="bmc_reset4" />
 			<feature name="mirroring" value="vertical" />
@@ -78748,6 +78767,7 @@ be better to redump them properly. -->
 		<description>4 in 1 (Alt 3)</description>
 		<year>19??</year>
 		<publisher>&lt;pirate&gt;</publisher>
+		<info name="usage" value="Press reset to switch games."/>
 		<part name="cart" interface="nes_cart">
 			<feature name="slot" value="bmc_reset4" />
 			<dataarea name="chr" size="32768">
@@ -80849,6 +80869,7 @@ to check why this is different -->
 		<description>Reset Based 4 in 1</description>
 		<year>19??</year>
 		<publisher>&lt;pirate&gt;</publisher>
+		<info name="usage" value="Press reset to switch games."/>
 		<part name="cart" interface="nes_cart">
 			<feature name="slot" value="bmc_reset4" />
 			<feature name="pcb" value="BMC-RESETBASED-4IN1" />

src/devices/bus/nes/multigame.cpp

@@ -32,6 +32,7 @@ DEFINE_DEVICE_TYPE(NES_ACTION52,       nes_action52_device,       "nes_action52"
 DEFINE_DEVICE_TYPE(NES_CALTRON6IN1,    nes_caltron_device,        "nes_caltron",        "NES Cart Caltron 6 in 1 PCB")
 DEFINE_DEVICE_TYPE(NES_RUMBLESTATION,  nes_rumblestat_device,     "nes_rumblestat",     "NES Cart Rumblestation PCB")
 DEFINE_DEVICE_TYPE(NES_SVISION16,      nes_svision16_device,      "nes_svision16",      "NES Cart Supervision 16 in 1 PCB")
+DEFINE_DEVICE_TYPE(NES_KN42,           nes_kn42_device,           "nes_kn42",           "NES Cart KN-42 PCB")
 DEFINE_DEVICE_TYPE(NES_N625092,        nes_n625092_device,        "nes_n625092",        "NES Cart N625092 PCB")
 DEFINE_DEVICE_TYPE(NES_A65AS,          nes_a65as_device,          "nes_a65as",          "NES Cart A65AS PCB")
 DEFINE_DEVICE_TYPE(NES_T262,           nes_t262_device,           "nes_t262",           "NES Cart T-262 PCB")
@@ -102,6 +103,11 @@ nes_svision16_device::nes_svision16_device(const machine_config &mconfig, const
 {
 }
 
+nes_kn42_device::nes_kn42_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
+	: nes_nrom_device(mconfig, NES_KN42, tag, owner, clock), m_latch(0)
+{
+}
+
 nes_n625092_device::nes_n625092_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
 	: nes_nrom_device(mconfig, NES_N625092, tag, owner, clock), m_latch1(0), m_latch2(0)
 {
@@ -406,6 +412,20 @@ void nes_svision16_device::pcb_reset()
 	m_latch2 = 0;
 }
 
+void nes_kn42_device::device_start()
+{
+	common_start();
+	save_item(NAME(m_latch));
+}
+
+void nes_kn42_device::pcb_reset()
+{
+	m_latch ^= 0x10;
+	prg16_89ab(m_latch);
+	prg16_cdef(m_latch | 0x0f);    // fixed to last bank for either game
+	chr8(0, CHRRAM);
+}
+
 void nes_n625092_device::device_start()
 {
 	common_start();
@@ -1215,6 +1235,32 @@ void nes_svision16_device::write_h(offs_t offset, uint8_t data)
 	update_prg();
 }
 
+/*-------------------------------------------------
+
+ Bootleg Board KN-42
+
+ Games: 2 in 1 - Big Nose & Big Nose Freaks Out
+
+ NES 2.0: mapper 381
+
+ In MAME: Supported.
+
+ TODO: Big Nose Freaks Out has timing issues like
+ many Camerica games. It happens with the singleton
+ dump and is unrelated to the bootleg board here.
+
+ -------------------------------------------------*/
+
+void nes_kn42_device::write_h(offs_t offset, u8 data)
+{
+	LOG_MMC(("kn42 write_h, offset: %04x, data: %02x\n", offset, data));
+
+	// this pcb is subject to bus conflict
+	data = account_bus_conflict(offset, data);
+
+	prg16_89ab(m_latch | (data & 0x07) << 1 | BIT(data, 4));
+}
+
 /*-------------------------------------------------
 
  Bootleg Board N625092
@@ -1265,7 +1311,6 @@ void nes_n625092_device::write_h(offs_t offset, uint8_t data)
 	}
 }
 
-
 /*-------------------------------------------------
 
  Board BMC-A65AS

src/devices/bus/nes/multigame.h

@@ -94,6 +94,27 @@ private:
 };
 
 
+// ======================> nes_kn42_device
+
+class nes_kn42_device : public nes_nrom_device
+{
+public:
+	// construction/destruction
+	nes_kn42_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
+
+	virtual void write_h(offs_t offset, u8 data) override;
+
+	virtual void pcb_reset() override;
+
+protected:
+	// device-level overrides
+	virtual void device_start() override;
+
+private:
+	u8 m_latch;
+};
+
+
 // ======================> nes_n625092_device
 
 class nes_n625092_device : public nes_nrom_device
@@ -1018,6 +1039,7 @@ DECLARE_DEVICE_TYPE(NES_ACTION52,       nes_action52_device)
 DECLARE_DEVICE_TYPE(NES_CALTRON6IN1,    nes_caltron_device)
 DECLARE_DEVICE_TYPE(NES_RUMBLESTATION,  nes_rumblestat_device)
 DECLARE_DEVICE_TYPE(NES_SVISION16,      nes_svision16_device)
+DECLARE_DEVICE_TYPE(NES_KN42,           nes_kn42_device)
 DECLARE_DEVICE_TYPE(NES_N625092,        nes_n625092_device)
 DECLARE_DEVICE_TYPE(NES_A65AS,          nes_a65as_device)
 DECLARE_DEVICE_TYPE(NES_T262,           nes_t262_device)

src/devices/bus/nes/nes_carts.cpp

@@ -352,6 +352,7 @@ void nes_cart(device_slot_interface &device)
 	device.option_add_internal("maxi15",           NES_MAXI15);        //  mapper 234
 	device.option_add_internal("rumblestation",    NES_RUMBLESTATION);    // mapper 46
 	device.option_add_internal("svision16",        NES_SVISION16);  // mapper 53
+	device.option_add_internal("kn42",             NES_KN42);
 	device.option_add_internal("n625092",          NES_N625092);
 	device.option_add_internal("a65as",            NES_A65AS);
 	device.option_add_internal("t262",             NES_T262);

src/devices/bus/nes/nes_ines.hxx

@@ -415,7 +415,7 @@ static const nes_mmc mmc_list[] =
 	// 378 8-in-1 multicart, which one?
 	// 379 35-in-1 multicart, similar to mapper 38
 	// 380 970630C multicart
-	// 381 KN-42 2-in-1 with the Big Nose games
+	{ 381, UNL_KN42 },             // 2-in-1 Big Nose games
 	// 382 830928C 5-in-1 and 9-in-1 multicarts
 	// 383 JY-014 multicart
 	// 384 4-in-1 VRC4 clone with Crisis Force

src/devices/bus/nes/nes_pcb.hxx

@@ -237,6 +237,7 @@ static const nes_pcb pcb_list[] =
 	{ "caltron6in1",      CALTRON_6IN1 },
 	{ "rumblestation",    RUMBLESTATION_BOARD },     // mapper 46
 	{ "svision16",        SVISION16_BOARD },
+	{ "kn42",             UNL_KN42 },
 	{ "n625092",          UNL_N625092 },
 	{ "a65as",            BMC_A65AS },
 	{ "t262",             BMC_T262 },

src/devices/bus/nes/nes_slot.h

@@ -102,7 +102,7 @@ enum
 	BMC_12IN1, BMC_4IN1RESET, BMC_42IN1RESET,
 	BMC_CTC09, BMC_K3046, BMC_SA005A, BMC_TJ03,
 	// Unlicensed
-	UNL_8237, UNL_CC21, UNL_AX5705, UNL_KOF97,
+	UNL_8237, UNL_CC21, UNL_AX5705, UNL_KN42, UNL_KOF97,
 	UNL_N625092, UNL_SC127, UNL_SMB2J, UNL_T230, UNL_MMALEE,
 	UNL_UXROM, UNL_MK2, UNL_XIAOZY, UNL_KOF96, UNL_FS6,
 	UNL_SF3, UNL_RACERMATE, UNL_EDU2K,