diff --git a/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h b/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
index da716d94c3..c90dc2d4cd 100644
--- a/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
+++ b/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
@@ -160,6 +160,7 @@ struct ag71xx {
 	u16			rx_buf_size;
 	u8			rx_buf_offset;
 	u8			tx_hang_workaround:1;
+	u8			builtin_switch:1;
 
 	struct net_device	*dev;
 	struct platform_device  *pdev;
diff --git a/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c b/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
index 8e387af27b..745a8d9ff4 100644
--- a/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
+++ b/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
@@ -868,6 +868,7 @@ __ag71xx_link_adjust(struct ag71xx *ag, bool update)
 	u32 cfg2;
 	u32 ifctl;
 	u32 fifo5;
+	unsigned int speed;
 
 	if (!ag->link && update) {
 		ag71xx_hw_stop(ag);
@@ -883,7 +884,7 @@ __ag71xx_link_adjust(struct ag71xx *ag, bool update)
 
 	cfg2 = ag71xx_rr(ag, AG71XX_REG_MAC_CFG2);
 	cfg2 &= ~(MAC_CFG2_IF_1000 | MAC_CFG2_IF_10_100 | MAC_CFG2_FDX);
-	cfg2 |= (ag->duplex) ? MAC_CFG2_FDX : 0;
+	cfg2 |= (ag->duplex || ag->builtin_switch) ? MAC_CFG2_FDX : 0;
 
 	ifctl = ag71xx_rr(ag, AG71XX_REG_MAC_IFCTL);
 	ifctl &= ~(MAC_IFCTL_SPEED);
@@ -891,7 +892,11 @@ __ag71xx_link_adjust(struct ag71xx *ag, bool update)
 	fifo5 = ag71xx_rr(ag, AG71XX_REG_FIFO_CFG5);
 	fifo5 &= ~FIFO_CFG5_BM;
 
-	switch (ag->speed) {
+	speed = ag->speed;
+	if (ag->builtin_switch)
+		speed = SPEED_1000;
+
+	switch (speed) {
 	case SPEED_1000:
 		cfg2 |= MAC_CFG2_IF_1000;
 		fifo5 |= FIFO_CFG5_BM;
@@ -1568,6 +1573,9 @@ static int ag71xx_probe(struct platform_device *pdev)
 		ag->pllregmap = NULL;
 	}
 
+	if (of_property_read_bool(np, "builtin-switch"))
+		ag->builtin_switch = 1;
+
 	ag->mac_base = devm_ioremap(&pdev->dev, res->start,
 				    res->end - res->start + 1);
 	if (!ag->mac_base)