Keyboard backlight on Debian 10?

Hi there, new to Linux and the community. I installed Debian 10 on my Librem 15v3 and the keyboard backlight is now not working (Fn+F10). I’ve tried sudo xset led 3 but that doesn’t light the keyboard, there’s nothing in Tweaks etc and can’t find anything obvious in /sys/ regarding keyboard backlights (though I did manage to switch off my screen backlight by editing one file, requiring a hard reboot :smiley: )

Could anybody point me in the right direction? Thanks