I've purchased an Akko keyboard and will be using that in my Linux environment from now on. I will continue to maintain the repo but should something happen, I'm unlikely to notice. Make sure to submit PRs with descriptions of the issue!
Enable Function Keys On The Keychron K2 Mechanical Keyboard Under Linux
Below, you'll find the steps required to create a systemd command that will run at boot to disable the media keys and restore f1-f12 functionality.
Step 1
Open a terminal window and enter the following command:
sudo nano /etc/systemd/system/keychron.service
Step 2
Paste the following into the window:
[Unit]
Description=The command to make the Keychron K2 work
[Service]
Type=oneshot
ExecStart=/bin/bash -c "echo 0 > /sys/module/hid_apple/parameters/fnmode"
[Install]
WantedBy=multi-user.target
Press ctrl+o and then ctrl+x to exit.
Step 3
In the terminal, type the following:
systemctl enable keychron
Step 4
That's it! A reboot, and you'll see that the function keys have been re-enabled.
Alternatively, run this command to see the changes right away:
systemctl start keychron
Closing Remarks
If you want to simply drag/drop the file that you create manually in the steps provided, I have it under the scripts folder in this repo. Download it and drop it in /etc/systemd/system/, doing Step 3 at the end.