diff --git a/target/linux/ar71xx/files/arch/mips/ath79/mach-tl-wr841n-v9.c b/target/linux/ar71xx/files/arch/mips/ath79/mach-tl-wr841n-v9.c
index c28afc6ceb..3e5c2a2522 100644
--- a/target/linux/ar71xx/files/arch/mips/ath79/mach-tl-wr841n-v9.c
+++ b/target/linux/ar71xx/files/arch/mips/ath79/mach-tl-wr841n-v9.c
@@ -109,12 +109,18 @@ static void __init tl_ap143_setup(void)
 	ath79_register_mdio(0, 0x0);
 
 	/* LAN */
+	ath79_eth1_data.phy_if_mode = PHY_INTERFACE_MODE_GMII;
+	ath79_eth1_data.duplex = DUPLEX_FULL;
+	ath79_switch_data.phy_poll_mask |= BIT(4);
 	ath79_init_mac(ath79_eth1_data.mac_addr, mac, 0);
 	ath79_register_eth(1);
 
 	/* WAN */
 	ath79_switch_data.phy4_mii_en = 1;
 	ath79_eth0_data.phy_if_mode = PHY_INTERFACE_MODE_MII;
+	ath79_eth0_data.duplex = DUPLEX_FULL;
+	ath79_eth0_data.speed = SPEED_100;
+	ath79_eth0_data.phy_mask = BIT(4);
 	ath79_init_mac(ath79_eth0_data.mac_addr, mac, 1);
 	ath79_register_eth(0);
 
diff --git a/target/linux/ar71xx/files/arch/mips/ath79/mach-wpj531.c b/target/linux/ar71xx/files/arch/mips/ath79/mach-wpj531.c
index bc13d7019f..e665a2e993 100644
--- a/target/linux/ar71xx/files/arch/mips/ath79/mach-wpj531.c
+++ b/target/linux/ar71xx/files/arch/mips/ath79/mach-wpj531.c
@@ -105,12 +105,19 @@ static void __init common_setup(void)
 	ath79_register_mdio(0, 0x0);
 
 	/* LAN */
+	ath79_eth0_data.duplex = DUPLEX_FULL;
+	ath79_eth0_data.phy_if_mode = PHY_INTERFACE_MODE_MII;
+	ath79_eth0_data.speed = SPEED_100;
+	ath79_eth0_data.phy_mask = BIT(4);
 	ath79_init_mac(ath79_eth0_data.mac_addr, mac, 0);
 	ath79_register_eth(0);
 
 	/* WAN */
 	ath79_switch_data.phy4_mii_en = 1;
+	ath79_eth1_data.duplex = DUPLEX_FULL;
 	ath79_eth1_data.phy_if_mode = PHY_INTERFACE_MODE_MII;
+	ath79_eth1_data.speed = SPEED_100;
+	ath79_switch_data.phy_poll_mask |= BIT(4);
 	ath79_init_mac(ath79_eth1_data.mac_addr, mac, 1);
 	ath79_register_eth(1);