Remap the function keys on an Anker slim bluetooth keyboard

99-AnkerBT-keyboard.hwdb

# Invert Anker A7726 Keyboard FN Keys
#
# This is the keyboard I bought:
# https://www.amazon.co.jp/gp/product/B00U260UR0/
# But the fn keys default to media keys which is very annoying.
#
# This will make the FN media keys function as F keys without pushing the FN
# button. Also you can still use the media keys by pushing the FN + Media key
# combination.
#
# Place this file in the udev hwdb directory:
# /etc/udev/hwdb.d/99-AnkerBT-keyboard.hwdb
#
# Run the following to apply the new mapping immediately:
#
# $ sudo systemd-hwdb update && sudo udevadm trigger
#
# CAUTION: Because Anker functions are split into 3 event devices, Gnome may
# not recognize the new keys until restarted.
#
# Basic process to find these mappings:
#
# The Anker keyboard will show up as three event devices. You can see all three
# after running:
#
# $ sudo evtest
#
# No device specified, trying to scan all of /dev/input/event*
# Available devices:
# /dev/input/event0:      Sleep Button
# /dev/input/event1:      Power Button
# /dev/input/event2:      Power Button
# ...
# /dev/input/event14:     Anker A7726 Keyboard
# /dev/input/event15:     Anker A7726 Consumer Control
# /dev/input/event16:     Anker A7726 System Control
#
# The media keys are part of "Consumer Control" while the normal F keys are
# part of "Keyboard".
#
# Select each and push each key to get the scancode output. This is the example
# for the "Back/Esc" key under "Consumer Control" device:
#
# Event: time 1564823511.343137, type 4 (EV_MSC), code 4 (MSC_SCAN), value c0224
# Event: time 1564823511.343137, type 1 (EV_KEY), code 158 (KEY_BACK), value 1
# Event: time 1564823511.343137, -------------- SYN_REPORT ------------
# Event: time 1564823511.367005, type 4 (EV_MSC), code 4 (MSC_SCAN), value c0224
# Event: time 1564823511.367005, type 1 (EV_KEY), code 158 (KEY_BACK), value 0
# Event: time 1564823511.367005, -------------- SYN_REPORT ------------
#
# The scan code is the "value c0224" part.
#
# Add the scan code to this file with the format:
#
# KEYBOARD_KEY_c0224=esc 
#
# to change the key function.
#
# The device match string parts can be found at the top of the evtest outputr:
# 
# Input device ID: bus 0x5 vendor 0x291a product 0x8502 version 0x11b
# Input device name: "Anker A7726 Keyboard"
#
# Be careful when converting this to the udev format because the letters must
# be in all caps and exactly 4 hex digits.
#
# To apply this mapping, use:
#
# $ sudo systemd-hwdb update && sudo udevadm trigger
#
# Re-run evtest to check the new mappings for each device:
#
# $ sudo evtest
#
# Gnome may not immediately reflect some of the mappings for some reason. So
# you may have to restart Gnome to see the changes in the desktop environment.
# As long as evtest shows the correct desired key code everything mapped
# correctly.
#
# These links are helpful:
# - https://github.com/hakimel/reveal.js/wiki/Linux-udev-keys-binding
# - https://wiki.archlinux.org/index.php/Map_scancodes_to_keycodes
# 
evdev:input:b0005v291Ap8502*
  KEYBOARD_KEY_c0224=esc # Original: KEY_BACK    
  KEYBOARD_KEY_c0223=f1 # Original: KEY_HOMEPAGE
  KEYBOARD_KEY_c0070=f2 # Original: KEY_BRIGHTNESSDOWN
  KEYBOARD_KEY_c006f=f3 # Original: KEY_BRIGHTNESSUP
  KEYBOARD_KEY_c0221=f4 # Original: KEY_SEARCH
  KEYBOARD_KEY_c01ae=f5 # Original: KEY_KEYBOARD
  KEYBOARD_KEY_c00b6=f6 # Original: KEY_PREVIOUSSONG
  KEYBOARD_KEY_c00cd=f7 # Original: KEY_PLAYPAUSE
  KEYBOARD_KEY_c00b5=f8 # Original: KEY_NEXTSONG
  KEYBOARD_KEY_c00e2=f9 # Original: KEY_MUT
  KEYBOARD_KEY_c00ea=f10 # Original: KEY_VOLUMEDOWN
  KEYBOARD_KEY_c00e9=f11 # Original: KEY_VOLUMEUP
  KEYBOARD_KEY_c0030=f12 # Original: KEY_POWER
  KEYBOARD_KEY_70029=back # Original: KEY_ESC
  KEYBOARD_KEY_7003a=homepage # Original: KEY_F1
  KEYBOARD_KEY_7003b=brightnessdown # Original: KEY_F2
  KEYBOARD_KEY_7003c=brightnessup # Original: KEY_F3
  KEYBOARD_KEY_7003d=search # Original: KEY_F4
  KEYBOARD_KEY_7003e=keyboard # Original: KEY_F5
  KEYBOARD_KEY_7003f=previoussong # Original: KEY_F6
  KEYBOARD_KEY_70040=playpause # Original: KEY_F7
  KEYBOARD_KEY_70041=nextsong # Original: KEY_F8
  KEYBOARD_KEY_70042=mute # Original: KEY_F9
  KEYBOARD_KEY_70043=volumedown # Original: KEY_F10
  KEYBOARD_KEY_70044=volumeup # Original: KEY_F11
  KEYBOARD_KEY_70045=power # Original: KEY_F12

Thanks! I bought a logitech k380 with this problem. Royal PIA. So I picked up an anker today seeing that it specifically has a "windows" mode that can be set on the keyboard. No good either. I put in your change and now the the function key work like they should.

Now I will try to follow what you've done and create a udev file for the logitech which is a much nicer keyboard.