diff --git a/src/mame/drivers/indigo.cpp b/src/mame/drivers/indigo.cpp
index f39d7c9ae33..a8a903f2849 100644
--- a/src/mame/drivers/indigo.cpp
+++ b/src/mame/drivers/indigo.cpp
@@ -627,7 +627,10 @@ MACHINE_CONFIG_END
 
 ROM_START( indigo3k )
 	ROM_REGION( 0x40000, "user1", 0 )
-	ROM_LOAD( "ip12prom.070-8088-xxx.bin", 0x000000, 0x040000, CRC(bb2f32ab) SHA1(d5f63dfbcca1206885753145ee34921b891b7eaf) )
+	ROM_SYSTEM_BIOS( 0, "401RevC", "SGI Version 4.0.1 Rev C LG1/GR2, Jul 9, 1992" ) // dumped over serial connection from boot monitor and swapped
+	ROM_LOAD16_WORD_SWAP( "ip12prom.070-8088-xxx.u56", 0x000000, 0x040000, CRC(25ca912f) SHA1(94b3753d659bfe50b914445cef41290122f43880) )
+	ROM_SYSTEM_BIOS( 1, "401RevD", "SGI Version 4.0.1 Rev D LG1/GR2, Mar 24, 1992" ) // dumped with EPROM programmer
+	ROM_LOAD16_WORD_SWAP( "ip12prom.070-8088-002.u56", 0x000000, 0x040000, CRC(ea4329ef) SHA1(b7d67d0e30ae8836892f7170dd4757732a0a3fd6) )
 ROM_END
 
 ROM_START( indigo4k )
@@ -636,5 +639,5 @@ ROM_START( indigo4k )
 ROM_END
 
 /*    YEAR  NAME      PARENT    COMPAT    MACHINE   INPUT     CLASS         INIT    COMPANY   FULLNAME */
-COMP( 1991, indigo3k, 0,        0,        indigo3k, indigo,   driver_device, 0,		"Silicon Graphics Inc", "IRIS Indigo (R3000, 33MHz, Ver. 4.0.5D Rev A)", MACHINE_NOT_WORKING | MACHINE_NO_SOUND )
+COMP( 1991, indigo3k, 0,        0,        indigo3k, indigo,   driver_device, 0,		"Silicon Graphics Inc", "IRIS Indigo (R3000, 33MHz)", MACHINE_NOT_WORKING | MACHINE_NO_SOUND )
 COMP( 1993, indigo4k, 0,        0,        indigo4k, indigo,   driver_device, 0, 		"Silicon Graphics Inc", "IRIS Indigo (R4400, 150MHz, Ver. 4.0.5D Rev A)", MACHINE_NOT_WORKING | MACHINE_NO_SOUND )