diff --git a/target/linux/realtek/files-6.18/drivers/net/mdio/mdio-realtek-otto.c b/target/linux/realtek/files-6.18/drivers/net/mdio/mdio-realtek-otto.c
index 7e5a7a79c85..37b6a95ae9c 100644
--- a/target/linux/realtek/files-6.18/drivers/net/mdio/mdio-realtek-otto.c
+++ b/target/linux/realtek/files-6.18/drivers/net/mdio/mdio-realtek-otto.c
@@ -916,8 +916,7 @@ static int rtmdio_map_ports(struct device *dev)
 			return dev_err_probe(dev, -EINVAL, "%pfwP no phy address\n",
 					     of_fwnode_handle(phy));
 
-		/* relaxed check as RTL839x uses MDIO addresses 0..51 */
-		if (smi_addr >= ctrl->cfg->num_phys)
+		if (smi_addr >= PHY_MAX_ADDR)
 			return dev_err_probe(dev, -EINVAL, "%pfwP illegal phy address\n",
 					     of_fwnode_handle(phy));