diff --git a/target/linux/ar71xx/files/arch/mips/ath79/dev-eth.c b/target/linux/ar71xx/files/arch/mips/ath79/dev-eth.c
index 5a0b950c1b..02c374a984 100644
--- a/target/linux/ar71xx/files/arch/mips/ath79/dev-eth.c
+++ b/target/linux/ar71xx/files/arch/mips/ath79/dev-eth.c
@@ -943,7 +943,6 @@ void __init ath79_register_eth(unsigned int id)
 		case ATH79_SOC_AR9341:
 		case ATH79_SOC_AR9342:
 		case ATH79_SOC_AR9344:
-		case ATH79_SOC_QCA9558:
 			if (id == 0)
 				pdata->mii_bus_dev = &ath79_mdio0_device.dev;
 			else
@@ -956,6 +955,10 @@ void __init ath79_register_eth(unsigned int id)
 			pdata->mii_bus_dev = &ath79_mdio1_device.dev;
 			break;
 
+		case ATH79_SOC_QCA9558:
+			/* don't assign any MDIO device by default */
+			break;
+
 		default:
 			pdata->mii_bus_dev = &ath79_mdio0_device.dev;
 			break;