-nintendo/vboy.cpp: Allow it to run unmapped reads with no cartridge.

-hash/gbcolor.xml: Added notes on what happens if you bypass the boot
 check for Rocket Games cartridges.

-bus/vboy/slot.cpp: Don't instantiate a cartridge device when no media
 is loaded.

hash/gameboy.xml

@@ -7509,7 +7509,8 @@ license:CC0
 		</part>
 	</software>
 
-	<software name="tamaosu">
+	<!-- unemulated speaker and real-time clock -->
+	<software name="tamaosu" supported="partial">
 		<!-- The game cart has an integrated speaker and a replaceable battery (CR2016). -->
 		<description>Game de Hakken!! Tamagotchi - Osutchi to Mesutchi (Japan)</description>
 		<year>1998</year>
@@ -27784,9 +27785,10 @@ patch the rom to 0x00 and 0x00....and at 0x0B3D also patch it to
 	</software>
 
 	<software name="lasama">
-		<description>La Sa Ma Chuan Qi - Story of Lasama (Taiwan)</description>
+		<description>Lāsàmǎ Chuánqí - Story of Lasama (Taiwan)</description>
 		<year>19??</year>
 		<publisher>GOWIN</publisher>
+		<info name="alt_title" value="拉薩瑪傳奇" />
 		<info name="serial" value="GS-04" />
 		<part name="cart" interface="gameboy_cart">
 			<feature name="slot" value="rom_lasama" />

hash/gbcolor.xml

@@ -24540,6 +24540,7 @@ license:CC0
     These were produced between 2000 and 2001 by Rocket Games, run by Datel Design
 -->
 
+	<!-- missing graphics in Karate Joe -->
 	<software name="atvrackj" supported="partial">
 		<description>ATV Racing &amp; Karate Joe (Europe)</description>
 		<year>200?</year>
@@ -24556,6 +24557,7 @@ license:CC0
 		</part>
 	</software>
 
+	<!-- missing graphics in Karate Joe -->
 	<software name="atvrackja" cloneof="atvrackj" supported="partial">
 		<description>ATV Racing &amp; Karate Joe (Europe, alt)</description>
 		<year>200?</year>
@@ -24587,6 +24589,7 @@ license:CC0
 		</part>
 	</software>
 
+	<!-- displays white screen rather than game selection menu - can still use Up/Down and Start to select game -->
 	<software name="fullhang" supported="partial">
 		<description>Full Time Soccer &amp; Hang Time Basketball (Europe)</description>
 		<year>200?</year>
@@ -24634,6 +24637,7 @@ license:CC0
 		</part>
 	</software>
 
+	<!-- missing graphics in Smash Out -->
 	<software name="pocksmrt" supported="partial">
 		<description>Pocket Smash Out &amp; Race Time (Europe)</description>
 		<year>200?</year>
@@ -24664,7 +24668,8 @@ license:CC0
 		</part>
 	</software>
 
-	<software name="karatej" supported="partial">
+	<!-- missing graphics make the game almost unplayable -->
+	<software name="karatej" supported="no">
 		<description>Karate Joe (Europe)</description>
 		<year>200?</year>
 		<publisher>Rocket Games</publisher>
@@ -24705,7 +24710,8 @@ license:CC0
 		</part>
 	</software>
 
-	<software name="sinkj" supported="partial">
+	<!-- Space Invasion hangs when starting a game, Karate Joe has missing graphics -->
+	<software name="sinkj" supported="no">
 		<description>Space Invasion &amp; Karate Joe (Europe)</description>
 		<year>200?</year>
 		<publisher>Rocket Games</publisher>
@@ -24721,6 +24727,7 @@ license:CC0
 		</part>
 	</software>
 
+	<!-- Space Invasion hangs when starting a game -->
 	<software name="sinpntr" supported="partial">
 		<description>Space Invasion &amp; Painter (Europe)</description>
 		<year>200?</year>
@@ -24737,7 +24744,8 @@ license:CC0
 		</part>
 	</software>
 
-	<software name="sinvasn" supported="partial">
+	<!-- hangs when starting a game -->
+	<software name="sinvasn" supported="no">
 		<description>Space Invasion (Europe)</description>
 		<year>200?</year>
 		<publisher>Rocket Games</publisher>

src/devices/bus/vboy/slot.cpp

@@ -126,27 +126,38 @@ void vboy_cart_slot_device::device_start()
 
 std::string vboy_cart_slot_device::get_default_card_software(get_default_card_software_hook &hook) const
 {
-	std::string const image_name(mconfig().options().image_option(instance_name()).value());
-	software_part const *const part(!image_name.empty() ? find_software_item(image_name, true) : nullptr);
-	if (part)
+	if (hook.image_file())
 	{
-		osd_printf_verbose("[%s] Found software part for image name '%s'\n", tag(), image_name);
-		for (rom_entry const &entry : part->romdata())
-		{
-			if (ROMENTRY_ISREGION(entry) && (entry.name() == "sram"))
-			{
-				osd_printf_verbose("[%s] Found 'sram' data area, enabling cartridge backup RAM\n", tag());
-				return "flatrom_sram";
-			}
-		}
+		// TODO: is there a header field or something indicating presence of save RAM?
+		osd_printf_verbose("[%s] Assuming plain ROM cartridge\n", tag());
+		return "flatrom";
 	}
 	else
 	{
-		osd_printf_verbose("[%s] No software part found for image name '%s'\n", tag(), image_name);
+		std::string const image_name(mconfig().options().image_option(instance_name()).value());
+		software_part const *const part(!image_name.empty() ? find_software_item(image_name, true) : nullptr);
+		if (part)
+		{
+			osd_printf_verbose("[%s] Found software part for image name '%s'\n", tag(), image_name);
+			for (rom_entry const &entry : part->romdata())
+			{
+				if (ROMENTRY_ISREGION(entry) && (entry.name() == "sram"))
+				{
+					osd_printf_verbose("[%s] Found 'sram' data area, enabling cartridge backup RAM\n", tag());
+					return "flatrom_sram";
+				}
+			}
+			osd_printf_verbose("[%s] No 'sram' data area found, assuming plain ROM cartridge\n", tag());
+			return "flatrom";
+		}
+		else
+		{
+			osd_printf_verbose("[%s] No software part found for image name '%s'\n", tag(), image_name);
+		}
 	}
 
-	osd_printf_verbose("[%s] Assuming plain ROM cartridge\n", tag());
-	return "flatrom";
+	// leave the slot empty
+	return std::string();
 }
 
 

src/mame/nintendo/vboy.cpp

@@ -1270,7 +1270,6 @@ void vboy_state::vboy(machine_config &config)
 
 	/* cartridge */
 	VBOY_CART_SLOT(config, m_cart, vboy_carts, nullptr);
-	m_cart->set_must_be_loaded(true);
 	m_cart->intcro().set_inputline(m_maincpu, 2);
 	m_cart->set_exp(m_maincpu, AS_PROGRAM, 0x0400'0000);
 	m_cart->set_chip(m_maincpu, AS_PROGRAM, 0x0600'0000);