I just got a new Librem 14 laptop and I am loving it except for the keyboard backlight that is not working. I’ve opened the lid and the connector is well seated. After removing it and putting it back again, I measured the voltage between GND and VCC and it is zero. Then I re-flashed the EC firmware using the bootable ISO. Also, looked in /sys/class/leds/librem_ec:kbd_backlight for any hints but nothing so far.
I did turn it on with Fn + F4. It is either OFF or 4 levels of brightness but it does not change for me. I am going to contact customer support as Frankly suggested. Just didn’t have time this week.