Installing RTL8812 (USB Wifi Dongle) on Ubuntu 18 and 20 LTS

Being a certified scrimp, reviving old PCs that will otherwise be thrown away by the Uni has become a hobby of mine. To connect these desktops at home where I only have access to wifi, I bought and used cheap USB wifi dongles from ebay. Unfortunately, as of the time I am wrote this article, they don't work right away on an Ubuntu machine and some work needs to be done. It did not help that there are a number of drivers out their ( 5 github pages!) so I had to test them one by one. The solution below is what worked for me. Make sure that no other RTL8812 driver is installed. I have tested these on Ubuntu 18.04 and 20.04 LTS.

1. Make sure we are talking about the same USB wifi dongle. At ebay it was labelled as “802.11ac AC600 USB WiFi Wireless Adapter Dongle WPS 5GHz Dual Band 5dBi Antenna”. See picture above. Furthermore, lsusb command returns something like below.

Bus 003 Device 005: ID 0bda:a811 Realtek Semiconductor Corp. 

2. Some prerequisites

sudo apt-get install build-essential dkms 

3. Install the driver

git clone https://github.com/gnab/rtl8812au
mv rtl8812au /usr/src/8812au-4.2.3
sudo dkms add -m 8812au -v 4.2.3
sudo dkms build -m 8812au -v 4.2.3
sudo dkms install -m 8812au -v 4.2.3

4. Check with:

sudo dkms status

5. Reboot your computer and the SSID should show up in the Ubuntu network manager.