diff --git a/src/mame/drivers/crospang.c b/src/mame/drivers/crospang.c
index 50c22ebdd59..4f0fa34b6d9 100644
--- a/src/mame/drivers/crospang.c
+++ b/src/mame/drivers/crospang.c
@@ -417,7 +417,7 @@ static MACHINE_DRIVER_START( crospang )
 	MDRV_SCREEN_ADD("main", RASTER)
 	MDRV_SCREEN_REFRESH_RATE(60)
 	MDRV_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(0))
-	MDRV_SCREEN_FORMAT(BITMAP_FORMAT_RGB15)
+	MDRV_SCREEN_FORMAT(BITMAP_FORMAT_INDEXED16)
 	MDRV_SCREEN_SIZE(64*8, 64*8)
 	MDRV_SCREEN_VISIBLE_AREA(0, 40*8-1, 0, 30*8-1)
 
@@ -455,7 +455,7 @@ static MACHINE_DRIVER_START( bestri )
 	MDRV_SCREEN_ADD("main", RASTER)
 	MDRV_SCREEN_REFRESH_RATE(60)
 	MDRV_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(0))
-	MDRV_SCREEN_FORMAT(BITMAP_FORMAT_RGB15)
+	MDRV_SCREEN_FORMAT(BITMAP_FORMAT_INDEXED16)
 	MDRV_SCREEN_SIZE(64*8, 64*8)
 	MDRV_SCREEN_VISIBLE_AREA(0, 40*8-1, 0, 30*8-1)