T440p keyboard backlight issue

[Kuzman]

I have a T440p which came with a non backlit keyboard, which I wanted to replace it with a backlit one. After installing the new keyboard the backlight wouldn't come on (i'm using Fn + spacebar, the keyboard has the light icon on the spacebar and the OS shows an icon for the backlight). I tried swapping it out with a friend's keyboard (from a t450s which was replaced due to a damaged key) but without any luck.

Could this be an issue with the motherboard or controller? What are my options?

Thanks!

[Thinkpad4by3]

My prediction is that its just a regedit fix. Probably is similar on how an regedit fix is needed to enable physical buttons when swapping X250 touchpad in X240.

[Kuzman]

Could you, please, point me in the right direction?

It doesn't work with either linux nor WIN10 (a clean install). This page https://support.lenovo.com/fr/en/solutions/ht104656 also states that it's a hardware feature. It doesn't even light up when in BIOS.
I would love to find a software fix for this, but it seems less and less plausible at this point.

[WVZR1]

I have a T440p which came with a non backlit keyboard, which I wanted to replace it with a backlit one. After installing the new keyboard the backlight wouldn't come on (i'm using Fn + spacebar, the keyboard has the light icon on the spacebar and the OS shows an icon for the backlight). I tried swapping it out with a friend's keyboard (from a t450s which was replaced due to a damaged key) but without any luck.

Could this be an issue with the motherboard or controller? What are my options?

Thanks!

My T440 NOT A P is this > "Ctrl" + Spacebar, First function is on, another is BRIGHTER and another is OFF.