Chosen Solution
Somehow the brightness control has disappeared from the display option as you can see on the picture. It’s an A1706 EMC 3163
any idea what would be the cause?
Sadly, Apples newer versions of macOS has now enabled display ID check so off brand (non-Apple units) now have issues. Talk with your supplier to see if they offer a solution, otherwise you’ll need to get a recycled real Apple display instead. And no, reverting to an older version won’t fix this. The alteration is within the systems firmware update and you can’t really roll it back.
