diff --git a/src/mame/drivers/naomi.cpp b/src/mame/drivers/naomi.cpp
index c2f9e7236a6..03a46b5dc15 100644
--- a/src/mame/drivers/naomi.cpp
+++ b/src/mame/drivers/naomi.cpp
@@ -2719,7 +2719,7 @@ MACHINE_CONFIG_END
  */
 
 static MACHINE_CONFIG_DERIVED( naomigd, naomi_base )
-	MCFG_NAOMI_GDROM_BOARD_ADD("rom_board", "gdrom", "pic", "naomibd_eeprom", WRITE8(dc_state, g1_irq))
+	MCFG_NAOMI_GDROM_BOARD_ADD("rom_board", ":gdrom", ":pic", "naomibd_eeprom", WRITE8(dc_state, g1_irq))
 MACHINE_CONFIG_END
 
 /*
diff --git a/src/mame/drivers/triforce.cpp b/src/mame/drivers/triforce.cpp
index 15bc9e48f20..3823f27179c 100644
--- a/src/mame/drivers/triforce.cpp
+++ b/src/mame/drivers/triforce.cpp
@@ -583,7 +583,7 @@ static MACHINE_CONFIG_START( triforce_base, triforce_state )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( triforcegd, triforce_base )
-	MCFG_NAOMI_GDROM_BOARD_ADD("rom_board", "gdrom", "pic", nullptr, NOOP)
+	MCFG_NAOMI_GDROM_BOARD_ADD("rom_board", ":gdrom", ":pic", nullptr, NOOP)
 MACHINE_CONFIG_END