diff --git a/hash/ibm5170.xml b/hash/ibm5170.xml
index a514cd7c15a..29bd4cdcfdf 100644
--- a/hash/ibm5170.xml
+++ b/hash/ibm5170.xml
@@ -8544,11 +8544,26 @@
 	</software>
 
 	<software name="chessm">
+		<!-- uses ChessMachine ISA card, not compatible with Final ChessCard -->
+		<!-- installer v3.3a, program v3.1, chess engine v2.20(The King) -->
+		<description>The ChessMachine (v3.1, The King v2.20)</description>
+		<year>1993</year>
+		<publisher>Tasc</publisher>
+		<info name="serial" value="WR.887.68.354" />
+		<info name="usage" value="Installer registration number is WR.887.68.354. ChessMachine ISA card required." />
+		<part name="flop1" interface="floppy_3_5">
+			<dataarea name="flop" size="737280">
+				<rom name="theking22.img" size="737280" crc="a93939a6" sha1="2f3927e50dd82b93ca3fa1436f5b664abc18d061"/>
+			</dataarea>
+		</part>
+	</software>
+
+	<software name="chessm23">
 		<!-- uses ChessMachine or Final ChessCard(ROM v3.6) ISA card -->
-		<description>The ChessMachine (Installer v3.0)</description>
+		<!-- installer v3.0, program v2.3, chess engine v2.1(Gideon) -->
+		<description>The ChessMachine (v2.3, Gideon v2.1)</description>
 		<year>1991</year>
 		<publisher>Tasc</publisher>
-		<info name="version" value="3.0" />
 		<info name="serial" value="WR.887.68.354" />
 		<info name="usage" value="Installer registration number is WR.887.68.354. ChessMachine/Final ChessCard ISA card required." />
 		<part name="flop1" interface="floppy_3_5">
@@ -8571,12 +8586,13 @@
 		</part>
 	</software>
 
-	<software name="chessm22">
+	<software name="chessm21">
 		<!-- uses ChessMachine or Final ChessCard(ROM v3.6) ISA card -->
-		<description>The ChessMachine (Installer v2.2)</description>
+		<!-- installer v2.2, program v2.1, chess engine v2.1(Gideon) -->
+		<!-- also includes optional older chess engine v0.5(The King) -->
+		<description>The ChessMachine (v2.1, Gideon v2.1)</description>
 		<year>1991</year>
 		<publisher>Tasc</publisher>
-		<info name="version" value="2.2" />
 		<info name="serial" value="50677" />
 		<info name="usage" value="ChessMachine/Final ChessCard ISA card required" />
 		<part name="flop1" interface="floppy_3_5">
@@ -9611,8 +9627,9 @@
 
 	<software name="finalchs">
 		<!-- uses Final ChessCard ISA card, ROM v3.6 (incompatible with older version) -->
-		<description>The Final ChessCard (Installer v2.0/Program v1.9)</description>
-		<year>1989</year>
+		<!-- installer v2.0, program v1.9 -->
+		<description>The Final ChessCard (v1.9)</description>
+		<year>1990</year>
 		<publisher>Tasc</publisher>
 		<info name="usage" value="Final ChessCard ISA card required" />
 		<part name="flop1" interface="floppy_3_5">
@@ -9622,15 +9639,16 @@
 		</part>
 	</software>
 
-	<software name="finalchso">
+	<software name="finalchs15">
 		<!-- uses Final ChessCard ISA card, ROM v2.0 (incompatible with newer version) -->
-		<description>The Final ChessCard (Program v1.5)</description>
+		<!-- installer v(none), program v1.5, install.exe and setup.exe are in Dutch -->
+		<description>The Final ChessCard (v1.5)</description>
 		<year>1989</year>
 		<publisher>Tasc</publisher>
 		<info name="usage" value="Final ChessCard ISA card required" />
 		<part name="flop1" interface="floppy_3_5">
 			<dataarea name="flop" size="737280">
-				<rom name="finalchso.img" size="737280" crc="4988a9c7" sha1="27483b574e73ca1bbd3984f7d1318ecc313a8b3e"/>
+				<rom name="finalchs15.img" size="737280" crc="4988a9c7" sha1="27483b574e73ca1bbd3984f7d1318ecc313a8b3e"/>
 			</dataarea>
 		</part>
 	</software>
diff --git a/src/devices/bus/isa/chessm.cpp b/src/devices/bus/isa/chessm.cpp
index 83033be95fe..9ed0f37eaf3 100644
--- a/src/devices/bus/isa/chessm.cpp
+++ b/src/devices/bus/isa/chessm.cpp
@@ -12,6 +12,12 @@ VLSI VY86C010-12QC (ARM2), seen with 30MHz XTAL, but XTAL label usually scratche
 It looks like Gideon 2.1 only sees up to 512KB RAM, The King up to 2MB RAM.
 Also seen with VY86C061PSTC (ARM6) @ 32MHz, very rare or prototype.
 
+3 models exist: SR, DR, EC. SR and DR are ISA cards, EC is an external module (serial port).
+It was also released for the Amiga.
+
+TODO:
+- add model DR (missing bootstrap ROM dump?)
+
 */
 
 #include "emu.h"
@@ -177,5 +183,5 @@ WRITE8_MEMBER(isa8_chessm_device::chessm_w)
 
 void isa8_chessm_device::chessm_mem(address_map &map)
 {
-	map(0x00380000, 0x00380000).r(m_sublatch, FUNC(generic_latch_8_device::read)).w(m_mainlatch, FUNC(generic_latch_8_device::write));
+	map(0x00380000, 0x00380000).mirror(0x00000008).r(m_sublatch, FUNC(generic_latch_8_device::read)).w(m_mainlatch, FUNC(generic_latch_8_device::write));
 }