diff --git a/hash/ibm5150.xml b/hash/ibm5150.xml
index b406a3d2d75..1ae08a659d2 100644
--- a/hash/ibm5150.xml
+++ b/hash/ibm5150.xml
@@ -10388,19 +10388,19 @@ Hangs after few seconds of gameplay
 		<part name="flop1" interface="floppy_3_5">
 			<feature name="part_id" value="CM Gideon" />
 			<dataarea name="flop" size="737280">
-				<rom name="gideon.img" size="737280" crc="c858c60e" sha1="dd482fd7efc60615c2836a4fef23c520454370db"/>
+				<rom name="gideon.img" size="737280" crc="6b903e6b" sha1="3753d34a52ff765393bcc4dd0d8e68dbb9dbb662"/>
 			</dataarea>
 		</part>
 		<part name="flop2" interface="floppy_3_5">
 			<feature name="part_id" value="CM The King" />
 			<dataarea name="flop" size="737280">
-				<rom name="theking.img" size="737280" crc="23bb50c0" sha1="9f5cb7c610fdf8404df5af59b101ed2a3a644ff2"/>
+				<rom name="theking.img" size="737280" crc="4412d875" sha1="245298ee049ba5a112f4e3f39d4e237d7fc99e6d"/>
 			</dataarea>
 		</part>
 		<part name="flop3" interface="floppy_3_5">
 			<feature name="part_id" value="Other" />
 			<dataarea name="flop" size="737280">
-				<rom name="other.img" size="737280" crc="660256ab" sha1="df629b5f0479082d25262e24af1fda7f025cf1f0"/>
+				<rom name="other.img" size="737280" crc="6bf45a36" sha1="cca48a34a22cf62b60ac545110262bd39a0e7e6b"/>
 			</dataarea>
 		</part>
 	</software>
diff --git a/src/mame/hegenerglaser/risc.cpp b/src/mame/hegenerglaser/risc.cpp
index da1bc98c863..93b801ae1c8 100644
--- a/src/mame/hegenerglaser/risc.cpp
+++ b/src/mame/hegenerglaser/risc.cpp
@@ -178,14 +178,21 @@ void risc_state::mrisc(machine_config &config)
 ROM_START( mrisc )
 	ROM_REGION( 0x20000, "maincpu", 0 )
 	// contains ChessMachine engine at 0x0-0x03fff + 0x10000-0x1c74f, concatenate those sections and make a .bin file,
-	// then it will work on ChessMachine software. It identifies as R E B E L ver. HG-021 03-04-92
-	ROM_LOAD("meph-risci-v1-2.bin", 0x00000, 0x20000, CRC(19c6ab83) SHA1(0baab84e5aa6999c24250938d207145144945fd5) )
+	// then it will work on ChessMachine software. It identifies as R E B E L version HG-021, 03-04-92
+	ROM_LOAD("meph-risci-v1-2", 0x00000, 0x20000, CRC(19c6ab83) SHA1(0baab84e5aa6999c24250938d207145144945fd5) )
+ROM_END
+
+ROM_START( mrisca )
+	ROM_REGION( 0x20000, "maincpu", 0 )
+	// contains ChessMachine engine at 0x0-0x03fff + 0x10000-0x1c6db, concatenate those sections and make a .bin file,
+	// then it will work on ChessMachine software. It identifies as R E B E L version HG-020, 14-03-92
+	ROM_LOAD("risc_1mb_rebel", 0x00000, 0x20000, CRC(f00b43ab) SHA1(8e9f3c99331b104af2008db1f0538ebaa97bc1e9) )
 ROM_END
 
 ROM_START( mrisc2 )
 	ROM_REGION( 0x20000, "maincpu", 0 )
 	// contains ChessMachine engine at 0x0-0x03fff + 0x10000-0x1cb7f, concatenate those sections and make a .bin file,
-	// then it will work on ChessMachine software. It identifies as R E B E L ver. 2.31 22-07-93, world champion Madrid 1992
+	// then it will work on ChessMachine software. It identifies as R E B E L version 2.31, 22-07-93, world champion Madrid 1992
 	ROM_LOAD("risc_2.31", 0x00000, 0x20000, CRC(9ecf9cd3) SHA1(7bfc628183037a172242c9589f15aca218d8fb12) )
 ROM_END
 
@@ -198,5 +205,7 @@ ROM_END
 *******************************************************************************/
 
 //    YEAR  NAME     PARENT   COMPAT  MACHINE   INPUT  CLASS       INIT        COMPANY, FULLNAME, FLAGS
-SYST( 1992, mrisc,   0,       0,      mrisc,    mrisc, risc_state, empty_init, "Hegener + Glaser / Tasc", "Mephisto Risc 1MB", MACHINE_SUPPORTS_SAVE )
-SYST( 1994, mrisc2,  mrisc,   0,      mrisc,    mrisc, risc_state, empty_init, "Hegener + Glaser / Tasc", "Mephisto Risc II",  MACHINE_SUPPORTS_SAVE )
+SYST( 1992, mrisc,   0,       0,      mrisc,    mrisc, risc_state, empty_init, "Hegener + Glaser / Tasc", "Mephisto Risc 1MB (v1.2)", MACHINE_SUPPORTS_SAVE )
+SYST( 1992, mrisca,  mrisc,   0,      mrisc,    mrisc, risc_state, empty_init, "Hegener + Glaser / Tasc", "Mephisto Risc 1MB (v1.0)", MACHINE_SUPPORTS_SAVE )
+
+SYST( 1994, mrisc2,  0,       0,      mrisc,    mrisc, risc_state, empty_init, "Hegener + Glaser / Tasc", "Mephisto Risc II", MACHINE_SUPPORTS_SAVE )
diff --git a/src/mame/mame.lst b/src/mame/mame.lst
index 7a5d30d97c0..e259cfd715b 100644
--- a/src/mame/mame.lst
+++ b/src/mame/mame.lst
@@ -19826,6 +19826,7 @@ polgar101                       // 1990 Mephisto Polgar 10MHz
 
 @source:hegenerglaser/risc.cpp
 mrisc                           // 1992 Mephisto RISC 1MB
+mrisca                          // 1992 Mephisto RISC 1MB
 mrisc2                          // 1994 Mephisto RISC II
 
 @source:hegenerglaser/roma2.cpp