Despite the Raspberry Pi 4 having built-in dual-band WiFi, many of our customers choose to purchase Dual-band USB WiFi adapters to improve their range or locate the ariel on an enclosure or similar.
Whilst many USB WiFi adapters are supported by drivers already installed within the Raspberry Pi OS, some newer drivers require manual setup.
Both of our dual-band WiFi adapters use the RTL881cu driver, and here's how you can get them working on a Raspberry Pi 4.
Setting up a RTL881cu USB Wifi adapter with the Raspberry Pi 4
Turn your Raspberry Pi on, connect to WiFi, open a new terminal window and follow the steps below. Don't plug the USB adapter in yet!
1. Update your Raspberry Pi
Make sure your Raspberry Pi is up to date before beginning, by using the following commands:
sudo apt-get update
sudo apt-get upgrade
2. Install the required software
You may already have the following packages installed, however it's best to check. Enter the following commands in your terminal window:
sudo apt install git
sudo apt install bc
sudo apt-get install dkms
3. Create a directory
Create a new directory for the driver by using the following command:
mkdir usbwifi
4. Access the directory
Access your new directory using the following command:
cd usbwifi
5. Download the repository
We'll be using a github repository for this install, which includes the driver we need. Enter the following command:
git clone https://github.com/whitebatman2/rtl8821CU
6. Access the downloaded repository
Enter the following command to access the downloaded driver repository:
cd rtl8821CU
7. Edit the driver before installing
We need to amend one of the install files to ensure the driver will work for the Raspberry Pi 4 (or 3). This is also described in the GitHub repo.
Enter the following command to open the file for editing:
sudo nano Makefile
If you're using a Raspberry Pi 4, you need to ensure the following lines are set correctly with y/n as per below:
CONFIG_PLATFORM_I386_PC = n
CONFIG_PLATFORM_ARM_RPI = y
CONFIG_PLATFORM_ARM_RPI3 = nOnce you've made those changes, hit ctrl + X and select 'y' to save the changes
8. Install the driver
Enter the following commands to install the driver. This part can take a few minutes so allow each command run:
make
(note: if it looks like the install gets stuck here after a few minutes, hit enter and see if the terminal moves on)
sudo make install
sudo modprobe 8821cu
9. Plug in the adapter
Once the install is complete, plug the adapter in to a USB port. If you now click on the WiFi icon, you should see both the internal (wlan0) wifi interface available, and the USB (wlan1) interface next to it.
