I was experimenting with two cheap Mediatek USB WiFi adapters in OpenWRT and had to experiment until I figured out which kmods were necessary to make it work, so documenting here in case someone else has the same issue…

Hardware #

First up, the adapters, you can find these on Aliexpress by searching for mt7921au or similar. They are both quite cheap (~5 USD and ~10 USD) and work out of the box in most normal Linux distributions – but not OpenWRT!

Noname 1800Mbps WiFi 6 USB Adapter 802.11AX:

EDUP 3000Mbps WiFi 6E Wireless Network Card USB:

Software #

The packages required for making them work is:

• kmod-mt7921-firmware
• kmod-mt7921u

I just added these under “Customize installed packages and/or first boot script” at the OpenWRT firmware selector, in my case for the Raspberry Pi 4B.

In my case I also wanted to use a special networking setup so I googled my way into a configuration I yolo’ed into “Script to run on first boot (uci-defaults)” at the same page. I wanted to disable dhcp and I wanted two VLAN interfaces. I then burned the generated factory image to a sd card and put into my Raspberry Pi 4B.

exec >/tmp/setup.log 2>&1

uci set network.lan.proto="dhcp"

uci set network.wifi="interface"
uci set network.wifi.device="eth0.100"
uci set network.wifi.proto="none"

uci set network.iot="interface"
uci set network.iot.device="eth0.200"
uci set network.iot.proto="none"

uci commit network

/etc/init.d/network restart

uci delete firewall.vlan100
uci delete firewall.vlan200

uci delete dhcp.lan

uci commit firewall
uci commit dhcp

/etc/init.d/firewall restart

echo "All done!"