diff --git a/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7981-cmcc-rax3000m.dtsi b/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7981-cmcc-rax3000m.dtsi
index 02034a930c..f4345b1d97 100644
--- a/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7981-cmcc-rax3000m.dtsi
+++ b/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7981-cmcc-rax3000m.dtsi
@@ -125,6 +125,7 @@
 	mtketh-wan = "eth1";
 	mtketh-lan = "eth0";
 	mtketh-max-gmac = <2>;
+	ext-devices-prefix = "usb", "wwan";
 	status = "okay";
 };