if (nesadapter->phy_type[mac_index] == NES_PHY_TYPE_1G) {
                        printk(PFX "%s: Programming mdc config for 1G\n", __func__);
                        tx_config = nes_read_indexed(nesdev, NES_IDX_MAC_TX_CONFIG);
+                       tx_config &= 0xFFFFFFE3;
                        tx_config |= 0x04;
                        nes_write_indexed(nesdev, NES_IDX_MAC_TX_CONFIG, tx_config);
                }
                    (nesadapter->phy_type[mac_index] == NES_PHY_TYPE_ARGUS)) {
                        /* setup 10G MDIO operation */
                        tx_config = nes_read_indexed(nesdev, NES_IDX_MAC_TX_CONFIG);
-                       tx_config |= 0x14;
+                       tx_config &= 0xFFFFFFE3;
+                       tx_config |= 0x15;
                        nes_write_indexed(nesdev, NES_IDX_MAC_TX_CONFIG, tx_config);
                }
                if ((nesadapter->phy_type[mac_index] == NES_PHY_TYPE_ARGUS)) {