After I upgraded to Sierra 10.12.4 yesterday, brightness is not working anymore. Instead the brighness is at the maximum value. Changing the brightness with Fn+F3 and Fn+Insert shows apple's brightness indicator changing, however without effect. I tried installing Rehabman's latest IntelBacklight.kext on my EFI partition, without luck unfortunately.
What are the steps I should take in order to fix the brightness in Sierra 10.12.4?
Thanks!