diff --git a/src/mame/drivers/segaybd.c b/src/mame/drivers/segaybd.c
index eeaed716a32..e0d74d56214 100644
--- a/src/mame/drivers/segaybd.c
+++ b/src/mame/drivers/segaybd.c
@@ -1702,7 +1702,7 @@ ROM_START( rchase )
 	ROM_LOAD16_BYTE( "ic25.bin",  0x000000, 0x20000, CRC(388b2365) SHA1(0f006f9120b96b8d8be968878ce1d6dd853cd977) )
 	ROM_LOAD16_BYTE( "ic24.bin",  0x000001, 0x20000, CRC(14dba5d4) SHA1(ad09c55273ab1105630f2f76019aedc234fb9292) )
 	ROM_LOAD16_BYTE( "ic27.bin",  0x040000, 0x20000, CRC(dc1cd5a4) SHA1(3b2b6afbeb7daa7c0cc75279bc495221c2508e25) )
-	ROM_LOAD16_BYTE( "ic26.bin",  0x040001, 0x20000, CRC(969fdb3a) SHA1(2d98f1bab2c20cad3d4c20ee2c4022d04fa9ffce) )
+	ROM_LOAD16_BYTE( "ic26.bin",  0x040001, 0x20000, BAD_DUMP CRC(969fdb3a) SHA1(2d98f1bab2c20cad3d4c20ee2c4022d04fa9ffce) ) //fails ROM checksum in service mode
 
 	ROM_REGION( 0x040000, "subx", 0 ) // X
 	ROM_LOAD16_BYTE( "ic81.bin",  0x000000, 0x20000, CRC(c5d525b6) SHA1(1fab7f761be67b67ee346a1af1f1fe12aef87dc5) )