• https://support.logi.com/hc/en-us/community/posts/360037026053-k380-use-all-f1-f2-etc-keys-as-standard-function-keys-
• https://www.radishlogic.com/tools/how-to-reverse-the-f-keys-of-logitech-k380-keyboard/

Linux

• https://askubuntu.com/questions/699138/logitech-k380-bluetooth-keyboard-make-function-keys-default
• https://www.radishlogic.com/tools/how-to-reverse-the-f-keys-of-logitech-k380-keyboard/

Turn on the device and read dmesg:

sudo dmesg

hid-generic 0005:046D:B342.002E: unknown main item tag 0x0
input: Keyboard K380 Keyboard as /devices/pci0000:00/0000:00:08.1/0000:04:00.3/usb1/1-4/1-4:1.0/bluetooth/hci0/hci0:256/0005:046D:B342.002E/input/input77
hid-generic 0005:046D:B342.002E: input,hidraw11: BLUETOOTH HID v42.01 Keyboard [Keyboard K380] on 38:fc:98:48:d0:e0

not quite working:

cat << EOT | sudo tee /etc/udev/rules.d/70-logi-k380.rules
ACTION=="add", SUBSYSTEM=="hidraw", KERNEL=="hidraw*", SUBSYSTEMS=="hid", KERNELS=="*:046D:B342.*", RUN+="/bin/bash -c \"echo -ne '\x10\xff\x0b\x1e\x00\x00\x00' > /dev/%k\""
EOT

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

This works

echo -ne “\x10\xff\x0b\x1e\x00\x00\x00” | sudo tee /dev/[the device] # function keys default echo -ne “\x10\xff\x0b\x1e\x01\x00\x00” | sudo tee /dev/[the device] # media keys default

Better

https://github.com/danb0b/external_k380-function-keys-conf

Finally

using udevadm info -q all -a /dev/hidraw2 I see that the KERNELS entry was for a parent device and that subsystems = HID was also for a parent device. I changed it to match entries I found with this

udevadm info -q all -n /dev/hidraw2

which gave me keys for the hidraw device it was showing up for at the time, that I could use.

ACTION==“add”, SUBSYSTEM==“hidraw”, KERNEL==“hidraw*”, DEVPATH==":046D:B342.", RUN+="/bin/bash -c "echo -ne ‘\x10\xff\x0b\x1e\x00\x00\x00’ | tee /dev/%k""