Option B would be to re-program the gMux IC (which is simply a Lattice LFXP2 FPGA), with a custom firmware to disable the GPU switching functionality.
A permanent fix to disable the defective dedicated AMD GPU on 2011 MacBook Pro models.
doslabelectronics.com
I know brightness doesn’t work but it was better the other option. I was running sierra for a long time but the accessing smb shares took to long. High Sierra fixes those problem.
I was using the nvram fix for a while but since that doesn’t work well with high sierra because of sleep. I didn’t want to solder anymore wires.