Using a RTL8812AUUSB WiFi dongle instead of built-in WiFi adaptor on RPI4

    I'm running LE11.06 on an RPI4.

    Given all the recent WiFi problems with LE10/11 on the Raspberry Pi (discussion here) I would like to try using an external WiFi dongle. Going through the junkbox I came across an Alpha Networks AWUS036AC (e.g. here). This is a dual-antenna long range model which, given that the "invalid key" problem is definitely related to lower signal strengths, might help. This dongle uses a Realtek RTL8812AU which I believe should be supported right out of the box. (Correct me if I'm wrong.)

    But how do I persuade LE to use this USB dongle rather than RPi's build-in WiFi adaptor?

    // FvW

    • Best Answer
    Code
    mount -o remount,rw /flash
echo "# disable wifi" >> /flash/config.txt
echo "dtoverlay=disable-wifi" >> /flash/config.txt
mount -o remount,ro /flash
reboot

    There are several options, but that ^ will disable the onboard WiFi in device-tree allowing the USB external dongle to appear as wlan0 instead of wlan1. The RTL8812AU should work out of box, but like all downstream Realtek drivers, there's no guarantee.

    Add "dtoverlay=disable-wifi" to config.txt - will disable the onboard wifi.

    And 2 things:

    1. If you have any possibility to use wired network, use it, it's far better than any wifi solution.

    2. Most probably the main issue is the tiny wifi antenna used on RPi boards. I soldered to my RPi3B board a wifi connector and tried with an external antenna. But that need a solid soldering skill. Working better than the USB-Wifi dongle. I think that can be made for RPi4B too. I tried this because had driver issue with the USB-Wifi dongle (some kind of cheap realtek RTL...).