#define VEND1_PORT_FUNC_ENABLES                0x8048
 #define PTP_ENABLE                     BIT(3)
+#define PHY_TEST_ENABLE                        BIT(0)
 
 #define VEND1_PORT_PTP_CONTROL         0x9000
 #define PORT_PTP_CONTROL_BYPASS                BIT(11)
 {
        const struct nxp_c45_regmap *regmap = nxp_c45_get_regmap(phydev);
 
+       phy_set_bits_mmd(phydev, MDIO_MMD_VEND1,
+                        VEND1_PORT_FUNC_ENABLES, PHY_TEST_ENABLE);
        return phy_set_bits_mmd(phydev, MDIO_MMD_VEND1, regmap->cable_test,
                                CABLE_TEST_ENABLE | CABLE_TEST_START);
 }
 
        phy_clear_bits_mmd(phydev, MDIO_MMD_VEND1, regmap->cable_test,
                           CABLE_TEST_ENABLE);
+       phy_clear_bits_mmd(phydev, MDIO_MMD_VEND1,
+                          VEND1_PORT_FUNC_ENABLES, PHY_TEST_ENABLE);
 
        return nxp_c45_start_op(phydev);
 }