Fixing ASUS TUF Gaming A16 Keyboard Backlight on Ubuntu 26.04

I recently installed Ubuntu 26.04 LTS on my ASUS TUF Gaming A16 (FA608UM) and noticed that the keyboard backlight wasn’t working.

Ubuntu detected the keyboard backlight, but the keys remained dark. Even the Fn + F2 and Fn + F3 shortcuts didn’t work.

After some troubleshooting, I found a solution.

My setup

Laptop: ASUS TUF Gaming A16 FA608UM
OS: Ubuntu 26.04 LTS
Kernel: 7.0.0-38-generic
Keyboard controller: ASUS 0B05:19B6

The problem

Ubuntu recognized the keyboard backlight:

ls /sys/class/leds/

The output included:

asus::kbd_backlight

However, setting the brightness manually didn’t help:

echo 3 | sudo tee /sys/class/leds/asus::kbd_backlight/brightness

The brightness value changed, but the keyboard remained dark.

The solution

The issue appears to be related to the keyboard controller’s lighting mode. Switching it using hidapitester fixed the problem.

1. Install dependencies

sudo apt update
sudo apt install -y git build-essential pkg-config libudev-dev libhidapi-dev

2. Download and compile hidapitester

cd /tmp
git clone https://github.com/todbot/hidapitester.git
cd hidapitester
make HIDAPI_WITH_SYSTEM_LIB=1
sudo install -m 0755 hidapitester /usr/local/bin/hidapitester

3. Enable the keyboard backlight

Run:

sudo hidapitester --vidpid 0B05/19B6 --open --send-feature 70,1 --close

Then set the brightness:

echo 3 | sudo tee /sys/class/leds/asus::kbd_backlight/brightness

That’s it! The keyboard backlight started working immediately.

The Fn + F2 and Fn + F3 shortcuts also started working, allowing me to adjust the brightness normally.

Does it survive a reboot?

Yes! I restarted the laptop, and the keyboard backlight continued working without running the commands again.

No startup scripts or additional services were needed.

Final thoughts

If you’re using an ASUS TUF Gaming A16 FA608UM with Ubuntu and your keyboard backlight isn’t working, this solution might help.

The important part was switching the keyboard controller’s lighting mode using hidapitester, rather than simply adjusting the brightness.

Note: This worked on my FA608UM with the hardware and kernel versions listed above. Other ASUS models or firmware versions may behave differently. Make sure your keyboard controller matches 0B05:19B6 before trying the HID command.

Hopefully, this saves someone else a few hours of troubleshooting!

Tags: Ubuntu, docs

Category: Docs