diff --git a/src/mame/drivers/snk6502.c b/src/mame/drivers/snk6502.c
index fb0f3ee2456..3db548e17ee 100644
--- a/src/mame/drivers/snk6502.c
+++ b/src/mame/drivers/snk6502.c
@@ -124,9 +124,7 @@ original rom dump came from.  Both the dedicated cabinet boards and the
 conversion kit boards for Nibbler never came with nor do the manuals for them
 list a "iC51" in the parts list breakdown.  In fact, sound roms between different
 games using the snk6502 custom sound can largely be interchanged with another
-using the same.  Currently in MAME, this IC51 from Pioneer Balloon is set as
-as OPTIONAL rom, allowing you to still play Nibbler (with/without music if you
-wish) without needing to adjust the source and recompile.
+using the same.
 
 ****************************************************************************
 
@@ -1352,7 +1350,6 @@ ROM_START( nibbler ) /* revision 9 - rom labels match manual part numbers/locati
 	ROM_LOAD( "g-0708-04.ic6",  0x0020, 0x0020, CRC(dacd592d) SHA1(c7709c680e2764885a40bc256d07dffc9e827cd6) ) /* background colors */
 
 	ROM_REGION( 0x1800, "snk6502", ROMREGION_ERASEFF )	/* sound ROMs */
-	ROM_LOAD_OPTIONAL( "sk7_ic51.bin", 0x0000, 0x0800, CRC(0345f8b7) SHA1(c00992dc7222cc53d9fdff4ab47a7abdf90c5116) ) /* Rom from Pioneer Balloon */
 	ROM_LOAD( "g-0959-44.ic52", 0x0800, 0x0800, CRC(87d67dee) SHA1(bd292eab3671cb953279f3136a450deac3818367) )
 	ROM_LOAD( "g-0959-45.ic53", 0x1000, 0x0800, CRC(33189917) SHA1(01a1b1693db0172609780daeb60430fa0c8bcec2) )
 ROM_END
@@ -1379,7 +1376,6 @@ ROM_START( nibbler8 ) /* revision 8 */
 	ROM_LOAD( "g-0708-04.ic6",  0x0020, 0x0020, CRC(dacd592d) SHA1(c7709c680e2764885a40bc256d07dffc9e827cd6) ) /* background colors */
 
 	ROM_REGION( 0x1800, "snk6502", ROMREGION_ERASEFF )	/* sound ROMs */
-	ROM_LOAD_OPTIONAL( "sk7_ic51.bin", 0x0000, 0x0800, CRC(0345f8b7) SHA1(c00992dc7222cc53d9fdff4ab47a7abdf90c5116) ) /* Rom from Pioneer Balloon */
 	ROM_LOAD( "g-0959-44.ic52", 0x0800, 0x0800, CRC(87d67dee) SHA1(bd292eab3671cb953279f3136a450deac3818367) )
 	ROM_LOAD( "g-0959-45.ic53", 0x1000, 0x0800, CRC(33189917) SHA1(01a1b1693db0172609780daeb60430fa0c8bcec2) )
 ROM_END
@@ -1406,7 +1402,33 @@ ROM_START( nibbler6 ) /* revision 6 */
 	ROM_LOAD( "g-0708-04.ic6",  0x0020, 0x0020, CRC(dacd592d) SHA1(c7709c680e2764885a40bc256d07dffc9e827cd6) ) /* background colors */
 
 	ROM_REGION( 0x1800, "snk6502", ROMREGION_ERASEFF )	/* sound ROMs */
-	ROM_LOAD_OPTIONAL( "sk7_ic51.bin", 0x0000, 0x0800, CRC(0345f8b7) SHA1(c00992dc7222cc53d9fdff4ab47a7abdf90c5116) ) /* Rom from Pioneer Balloon */
+	ROM_LOAD( "g-0959-44.ic52", 0x0800, 0x0800, CRC(87d67dee) SHA1(bd292eab3671cb953279f3136a450deac3818367) )
+	ROM_LOAD( "g-0959-45.ic53", 0x1000, 0x0800, CRC(33189917) SHA1(01a1b1693db0172609780daeb60430fa0c8bcec2) )
+ROM_END
+
+ROM_START( nibbler6 ) /* revision 6 + extra soundrom */
+	ROM_REGION( 0x10000, "maincpu", 0 )
+	ROM_LOAD( "ic12",           0x3000, 0x1000, CRC(ac6a802b) SHA1(ac1072e30994f13097663dc24d9d1dc35a95d874) )
+	ROM_LOAD( "ic7",            0x4000, 0x1000, CRC(35971364) SHA1(6430c7be9e5f47d3f1f2cc157d949246e4085e8b) )
+	ROM_LOAD( "ic8",            0x5000, 0x1000, CRC(6b33b806) SHA1(29444e45bf5a6ab1d86e0aa19dc6c1bc64ba633f) )
+	ROM_LOAD( "ic9",            0x6000, 0x1000, CRC(91a4f98d) SHA1(678c7e8c91a7fdba8dc2faff4192eb0964abdb3f) )
+	ROM_LOAD( "ic10",           0x7000, 0x1000, CRC(a151d934) SHA1(6681bdcd84cf62b40b2430ff530cb3c9aa36656c) )
+	ROM_LOAD( "ic14",           0x8000, 0x1000, CRC(063f05cc) SHA1(039ac1b007cb817ae0902484ca611ae7076930d6) )
+	ROM_RELOAD(                 0xf000, 0x1000 )	/* for the reset and interrupt vectors */
+	ROM_LOAD( "g-0960-54.ic15", 0x9000, 0x1000, CRC(7205fb8d) SHA1(bc341bc11a383aa8b8dd7b2be851907a3ec56f8b) )
+	ROM_LOAD( "g-0960-55.ic16", 0xa000, 0x1000, CRC(4bb39815) SHA1(1755c28d7d300524ab839aedcc744254544e9c19) )
+	ROM_LOAD( "g-0960-56.ic17", 0xb000, 0x1000, CRC(ed680f19) SHA1(b44203585f32ebe2a3bf0597eac7c0faa7e81a92) )
+
+	ROM_REGION( 0x2000, "gfx1", 0 )
+	ROM_LOAD( "g-0960-57.ic50", 0x0000, 0x1000, CRC(01d4d0c2) SHA1(5a8026210a872351ce4e39e27f6479d3ca0689e2) )
+	ROM_LOAD( "g-0960-58.ic51", 0x1000, 0x1000, CRC(feff7faf) SHA1(50005502578a4ea9b9c8f36998670b787d2d0b20) )
+
+	ROM_REGION( 0x0040, "proms", 0 )
+	ROM_LOAD( "g-0708-05.ic7",  0x0000, 0x0020, CRC(a5709ff3) SHA1(fbd07b756235f2d03aea3d777ca741ade54be200) ) /* foreground colors */
+	ROM_LOAD( "g-0708-04.ic6",  0x0020, 0x0020, CRC(dacd592d) SHA1(c7709c680e2764885a40bc256d07dffc9e827cd6) ) /* background colors */
+
+	ROM_REGION( 0x1800, "snk6502", ROMREGION_ERASEFF )	/* sound ROMs */
+	ROM_LOAD( "sk7_ic51.bin",   0x0000, 0x0800, CRC(0345f8b7) SHA1(c00992dc7222cc53d9fdff4ab47a7abdf90c5116) ) /* Rom from Pioneer Balloon */
 	ROM_LOAD( "g-0959-44.ic52", 0x0800, 0x0800, CRC(87d67dee) SHA1(bd292eab3671cb953279f3136a450deac3818367) )
 	ROM_LOAD( "g-0959-45.ic53", 0x1000, 0x0800, CRC(33189917) SHA1(01a1b1693db0172609780daeb60430fa0c8bcec2) )
 ROM_END
@@ -1433,7 +1455,6 @@ ROM_START( nibblero ) /* revision 8 */
 	ROM_LOAD( "g-0708-04.ic6",  0x0020, 0x0020, CRC(dacd592d) SHA1(c7709c680e2764885a40bc256d07dffc9e827cd6) ) /* background colors */
 
 	ROM_REGION( 0x1800, "snk6502", ROMREGION_ERASEFF )	/* sound ROMs */
-	ROM_LOAD_OPTIONAL( "sk7_ic51.bin", 0x0000, 0x0800, CRC(0345f8b7) SHA1(c00992dc7222cc53d9fdff4ab47a7abdf90c5116) ) /* Rom from Pioneer Balloon */
 	ROM_LOAD( "g-0959-44.ic52", 0x0800, 0x0800, CRC(87d67dee) SHA1(bd292eab3671cb953279f3136a450deac3818367) )
 	ROM_LOAD( "g-0959-45.ic53", 0x1000, 0x0800, CRC(33189917) SHA1(01a1b1693db0172609780daeb60430fa0c8bcec2) )
 ROM_END
@@ -1460,4 +1481,5 @@ GAME( 1982, pballoonr,pballoon, pballoon, pballoon, 0, ROT90, "SNK (Rock-Ola lic
 GAME( 1982, nibbler,  0,        nibbler,  nibbler,  0, ROT90, "Rock-Ola", "Nibbler (rev 9)", 0 )
 GAME( 1982, nibbler8, nibbler,  nibbler,  nibbler8, 0, ROT90, "Rock-Ola", "Nibbler (rev 8)", 0 )
 GAME( 1982, nibbler6, nibbler,  nibbler,  nibbler6, 0, ROT90, "Rock-Ola", "Nibbler (rev 6)", 0 )
+GAME( 1982, nibblerp, nibbler,  nibbler,  nibbler6, 0, ROT90, "Rock-Ola", "Nibbler (Pioneer Balloon conversion)", 0 )
 GAME( 1983, nibblero, nibbler,  nibbler,  nibbler8, 0, ROT90, "Rock-Ola (Olympia license)", "Nibbler (Olympia - rev 8)", 0 )
diff --git a/src/mame/mame.lst b/src/mame/mame.lst
index bca2ce0aa99..aad48fcd982 100644
--- a/src/mame/mame.lst
+++ b/src/mame/mame.lst
@@ -6715,6 +6715,7 @@ pballoonr		// (c) 1982 SNK (Rock-Ola license)
 nibbler			// (c) 1982 Rock-ola (version 9)
 nibbler8		// (c) 1982 Rock-ola (version 8)
 nibbler6		// (c) 1982 Rock-ola (vresion 6)
+nibblerp		// (c) 1982 Rock-ola (pballoon conversion)
 nibblero		// (c) 1983 Olympia/Rock-Ola (version 8)
 
 // later SNK games, each game can be identified by PCB code and ROM