Black Screen on boot bug

[mxbi]

A few hours after installing CM12 the screen suddenly went black, with the backlight turned off.

I have confirmed the phone is still turned on and working, I still get vibration feedback by opening the power menu and I can connect to it via bluetooth. Restarting simply shows the cyanogenmod booting logo, then when it would usually open the UI, there is just a black screen.

Wiping dalvik/cache and reflashing cm12 hasn't helped (note that the 'android optimizing apps' still shows up and when it finishes it goes back to a black screen)

This may have been caused by the Adaptive Brightness feature

[NicholasPace]

This happens on many (maybe all) devices running cm with adaptive brightness enabled.