I juste have the same problem since 2 hours... In my case, it's after boot my phone, I reduce a little bit the luminosity and hop.. screen off... I tried to reboot the phone, without results
I have the last version (not advanced) of fairphone; the LED is still working; when I remove the battery and make my phone charge (but it has enough battery) the screen in on (with the animation of charging) but when I reboot my phone, I see the blue animation -start a mouvement) and then screen off.. I tried to remove and put again the screen but it doesn't work; I tried long press the power button, but it doesn't work; I tried to remove and put against, without results..
I tried to pu my code, scrool the scroll bar and increase luminosity (without see what I was doing) but it didn't work... Maybe a factory reset but I hope there is an other way
Is there a solution? I read the other post with this bug, but I don't understand all the english words; and I don't know is a solution exists... please answer me if there is a solution