DKMS Device Driver for WiFi Modules

Automatically rebuilds and installs on kernel updates. DKMS is in official sources of Ubuntu, for installation do:

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sudo apt install build-essential dkms git

Update apt database with apt using the following command.

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sudo apt update

After updating apt database, We can install rtl8812au-dkms using apt by running the following command:

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sudo apt -y install rtl8812au-dkms

Clone the driver source from GitHub and the driver source must be copied to /usr/src/8812au-4.2.2

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git clone https://github.com/gnab/rtl8812au
sudo cp -a rtl8812au /usr/src/8812au-4.2.2

Then add it to DKMS:

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sudo dkms add -m 8812au -v 4.2.2
sudo dkms build -m 8812au -v 4.2.2
sudo dkms install -m 8812au -v 4.2.2

Clone the driver source from GitHub.

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git clone https://github.com/brektrou/rtl8821CU
cd rtl8821CU

Add this to DKMS.

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sudo ./dkms-install.sh

If steps above worked fine and in order to avoid periodically having to make usb_modeswitch you can make it permanent
Then add the following contents to enable the WiFi feature in every boot.

Before editing usb_modeswitch rules, check whether it is on the list or not.

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grep ".0bda.*1a2b" /lib/udev/rules.d/40-usb_modeswitch.rules

If it shows us as below, you don't need to add the line.

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ATTR{idVendor}=="0bda", ATTR{idProduct}=="1a2b", RUN+="usb_modeswitch '/%k'"

If the line doesn't show up, edit usb_modeswitch rules.

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sudo vi /lib/udev/rules.d/40-usb_modeswitch.rules

Append before the end line LABEL=“modeswitch_rules_end” the following:

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# Realtek 8821CU Wifi AC USB
ATTR{idVendor}=="0bda", ATTR{idProduct}=="1a2b", RUN+="/usr/sbin/usb_modeswitch '/%k'"

Reload udev rules to apply the changes without rebooting.

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sudo udevadm control --reload-rules && sudo udevadm trigger

1. GitHub for rtl8812au driver and DKMS
2. GitHub for rtl8821cu driver and DKMS