Just updated to High Sierra, did everything I saw in the guide but got a black screen. I have a GTX 960. I found a fix so thought I would share what worked and what did not work for me.
Luckily I own Apple Remote Desktop and an old iMac. While there is indeed a black screen I can remote control from my iMac and tinker with the machine. I tried the following things that I read in this thread.
- enable iGPU and disable again
- Changed nvidiaweb from true to yes
- Download and install the latest lilu.kext
- Update NvidiaGraphicsFixup BINGO!
Ok, now I have video I can work on getting my sound back