Chosen Solution
So I’m here with a Mid 2015 MacBook Pro 15’’ with dual graphics and I came to this problem where the brightness slider is missing. I can’t seem to adjust the brightness at all with the F1 and F2 keys. Also, when closing the lid, the backlight doesn’t want to come back on, even though it’s in working order. Display doesn’t seem to dim either, it always stay at full brightness no matter what. Also on a side note, I kept getting these Sleep Wake Failure in EFI errors every time I put the Mac to sleep, which means I gotta restart every time I try to wake up the MacBook. Tried to perform SMC and NVRAM resets, but it didn’t work. Here is what I see when going to the display settings.
Why did you force the NVRAM setting with the terminal command? You may need to be more aggressive in flushing the NVRAM. Disconnect the MagSafe charger and battery, then press the power button to fully discharge the circuit for a good minute. Now plug in the MagSafe charger, the system should spontaneously startup. Shut it down reconnect the battery and restart did that alter anything? Otherwise you may have fixed the bent pin something may have been damaged in the logic.
