diff --git a/src/mame/drivers/megatech.c b/src/mame/drivers/megatech.c
index 02a61342eca..27cf39abb4d 100644
--- a/src/mame/drivers/megatech.c
+++ b/src/mame/drivers/megatech.c
@@ -791,7 +791,11 @@ MACHINE_CONFIG_END
 	ROM_SYSTEM_BIOS( 1, "ver0a", "Ver 0 Rev A" ) \
 	ROMX_LOAD( "epr-12263a.20", 0x000000, 0x8000, CRC(07c3f423) SHA1(50c28bbc2d4349c820d988ae3f20aae3f808545f), ROM_BIOS(2)) \
 	ROM_SYSTEM_BIOS( 2, "ver0b", "Ver 0 Rev B" ) \
-	ROMX_LOAD( "epr-12263b.20", 0x000000, 0x8000, CRC(ca26c87a) SHA1(987a18bede6e54cd73c4434426eb6c302a37cdc5), ROM_BIOS(3))
+	ROMX_LOAD( "epr-12263b.20", 0x000000, 0x8000, CRC(ca26c87a) SHA1(987a18bede6e54cd73c4434426eb6c302a37cdc5), ROM_BIOS(3)) \
+	ROM_SYSTEM_BIOS( 3, "ver0aa","Ver 0 Rev B (alt?)" ) \
+	ROMX_LOAD( "EPR-12604a.", 0x000000, 0x8000, CRC(884e4aa5) SHA1(c9008c431a937c084fb475273093ca0b434b5f47), ROM_BIOS(4))
+
+
 /* no games */
 ROM_START( megatech )
 	MEGATECH_BIOS