To install GC adapter udev rules on Linux, enter the following string of commands:

sudo rm -f /etc/udev/rules.d/51-gcadapter.rules && sudo touch /etc/udev/rules.d/51-gcadapter.rules && echo 'SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ATTRS{idVendor}=="057e", ATTRS{idProduct}=="0337", MODE="0666"' | sudo tee /etc/udev/rules.d/51-gcadapter.rules > /dev/null && sudo udevadm control --reload-rules

There is no output, so once it is finished restart Dolphin and test your adapter.

If your adapter still doesn't work then try running the command below or restarting your computer.

sudo systemctl restart udev.service