Keychron K5 Function Keys + Unstable Bluetooth fix - Ubuntu 22.04

If you have problem getting the F1 - F12 (Function) keys to work, and unstable bluetooth connection on your new Keychron K5 keyboard, this will hopefully help you.

Here are the fixes that worked for me on Ubuntu 22.04.

Fixing top row keys as F1 to F12

So you can actually use the function key row as function keys:

1. Set keyboard to Windows mode (use hardware switch)
2. Hold Fn + X + L for 4 seconds to switch to "Function" mode

3. Apply the fix temporarily --> check if it's working:
   

   echo 0 | sudo tee /sys/module/hid_apple/parameters/fnmode
   

4. Apply the fix permanently:
   

   echo "options hid_apple fnmode=0" | sudo tee -a /etc/modprobe.d/hid_apple.conf
   sudo update-initramfs -u
   

5. Reboot (to verify)

Fixing unstable Bluetooth Connection

Before this fix the keyboard would randomly disconnect.

After this fix, not a single glitch the entire workday 😋

1. Enable fast connect:

   Edit /etc/bluetooth/main.conf - uncomment and set these values:
   

   FastConnectable = true
   ReconnectAttempts=7
   ReconnectIntervals=1, 2, 4
   

2. Disable bluetooth auto suspend
   

   echo "options btusb enable_autosuspend=n" | sudo tee /etc/modprobe.d/btusb_disable_autosuspend.conf
   sudo update-initramfs -u
   

3. Restart bluetooth
   

   sudo modprobe -r btusb
   sudo systemctl restart bluetooth
   sudo modprobe btusb
   

4. Factory reset keyboard (Hold Fn + Z + J for 4 seconds) --> Re-pair keyboard

   This makes no sense but it did seem to make a difference...

Credits

This post is possible thanks to these awesome people:

• Mike Shade
• andrebrait