Make function keys default on Logitech k380 bluetooth keyboard.

1. First install gcc. On Ubuntu run:

sudo apt install gcc

2. Download installation files https://github.com/jergusg/k380-function-keys-conf/releases/ (Source code).

3. Connect your K380 keyboard via bluetooth to your computer.

4. Run build.sh

./build.sh

5. To switch keyboard's upper keys to F-keys run:

sudo ./k380_conf -d /dev/hidrawX -f on

Where X is number of your keyboard hidraw interface. Possibly 0, 1, 2, 3.

Follow instructions your received when you built k380_conf:

sudo cp /your-build-path/80-k380.rules /etc/udev/rules.d/ && sudo udevadm control --reload

Now, when you reconnect your keyboard it will be automatically switched to F-keys mode.

http://www.trial-n-error.de/posts/2012/12/31/logitech-k810-keyboard-configurator/

https://github.com/embuc/k480_conf

look there for more information