diff --git a/drivers/ata/pata_hpt366.c b/drivers/ata/pata_hpt366.c
index 7a6ff3d..6f7d34a 100644
--- a/drivers/ata/pata_hpt366.c
+++ b/drivers/ata/pata_hpt366.c
@@ -396,7 +396,7 @@
 		.flags = ATA_FLAG_SLAVE_POSS,
 		.pio_mask = 0x1f,
 		.mwdma_mask = 0x07,
-		.udma_mask = 0x1f,
+		.udma_mask = ATA_UDMA4,
 		.port_ops = &hpt366_port_ops
 	};
 	struct ata_port_info info = info_hpt366;