diff --git a/src/mame/drivers/naomi.cpp b/src/mame/drivers/naomi.cpp
index a61278f77de..a6fd8205c72 100644
--- a/src/mame/drivers/naomi.cpp
+++ b/src/mame/drivers/naomi.cpp
@@ -7759,7 +7759,7 @@ ROM_START( vtennis2 )
 	DISK_IMAGE_READONLY( "gds-0015a", 0, SHA1(5db1ef70b6db63f8a15e1d64cdf0170e80209eb4) )
 
 	ROM_REGION( 0x4000, "pic", ROMREGION_ERASEFF)
-	ROM_LOAD("317-0318-exp.pic", 0x00, 0x4000, CRC(83de4047) SHA1(1808ac0d8353b92296de37f98b490a42a0e141cf) )
+	ROM_LOAD("317-0318-com.pic", 0x00, 0x4000, CRC(83de4047) SHA1(1808ac0d8353b92296de37f98b490a42a0e141cf) )
 
 ROM_END
 
@@ -7815,7 +7815,7 @@ ROM_START( lupinsho )
 	DISK_IMAGE_READONLY( "gds-0018", 0, BAD_DUMP SHA1(0633a99a666f363ab30450a76b9753685d6b1f57) )
 
 	ROM_REGION( 0x4000, "pic", ROMREGION_ERASEFF)
-	ROM_LOAD("317-0332-j.pic", 0x00, 0x4000, CRC(f71cb2fc) SHA1(281b3b3b03edf9a39e380976de528b7c9674de53) )
+	ROM_LOAD("317-0332-jpn.pic", 0x00, 0x4000, CRC(f71cb2fc) SHA1(281b3b3b03edf9a39e380976de528b7c9674de53) )
 ROM_END
 
 ROM_START( vathlete )
diff --git a/src/mame/drivers/segas16b.cpp b/src/mame/drivers/segas16b.cpp
index b890622dbe3..171530fa06e 100644
--- a/src/mame/drivers/segas16b.cpp
+++ b/src/mame/drivers/segas16b.cpp
@@ -8139,6 +8139,7 @@ ROM_END
 //  Wonder Boy III, Sega System 16B
 //  CPU: FD1094 (317-0085)
 //  ROM Board type: 171-5358
+// Sega ID# for ROM board: 834-6854
 //
 //  Pos.   Silk        Type        Part                Pos.   Silk        Type        Part
 //  A1     EPR-12198   27C512      68000 program       B1     EPR-12190   27C512      Sprite data
diff --git a/src/tools/chdman.cpp b/src/tools/chdman.cpp
index 4af9f6f378f..addfe14a913 100644
--- a/src/tools/chdman.cpp
+++ b/src/tools/chdman.cpp
@@ -1790,6 +1790,10 @@ static void do_create_hd(parameters_t &params)
 		cylinders = (identdata[3] << 8) | identdata[2];
 		heads = (identdata[7] << 8) | identdata[6];
 		sectors = (identdata[13] << 8) | identdata[12];
+
+		// ignore CHS for > 8GB drives
+		if (input_file && filesize > 0x200000000)
+			cylinders = 0;
 	}
 
 	// extract geometry from the parent if we have one