diff --git a/target/linux/mediatek/files-5.4/drivers/net/phy/mediatek-2p5ge.c b/target/linux/mediatek/files-5.4/drivers/net/phy/mediatek-2p5ge.c
index 251a412..d292dbe 100644
--- a/target/linux/mediatek/files-5.4/drivers/net/phy/mediatek-2p5ge.c
+++ b/target/linux/mediatek/files-5.4/drivers/net/phy/mediatek-2p5ge.c
@@ -74,7 +74,10 @@
 	if (ret)
 		return ret;
 
-	linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Half_BIT,
+	/* We don't support HDX at MAC layer on mt798x.
+	 * So mask phy's HDX capabilities, too.
+	 */
+	linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT_Full_BIT,
 			 phydev->supported);
 	linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Full_BIT,
 			 phydev->supported);