There is an acknowledged bug in the current version of Cody Kreiger's Open-Source gfxcardstatus, and the developer has confessed he does not have time to fix it right now.
There is a fork off the main build by steveschow available that seems to fix that problem for current versions of MacOS such as ElCapitan and Sierra. He provides a finished .app for direct download -- you do not have to compile anything.
https://github.com/steveschow/gfxCardStatus/releases
Also note that if your Mac does not run long enough to allow gfxcardstatus to be added, this is not really practical.
In addition, Steve Schow writes that he has abandoned further development -- because there are better solutions available [for both the 2010 model and 2011 models].
2011 model:
the use of ArchLinux bootable CD to gain access to and re-write the EFI on the drive, and permanently disable the discrete graphics chip. This page and scroll down past the list to the blog:
http://github.com/steveschow/gfxCardStatus
There are two similar procedure listed. I used the second from MacRumors as it seemed easier. I have made the Arch Linux bootable CD on another Mac, and tried this approach. I now have a perfectly-functioning MacBook Pro late 2011 15-in model with Discrete Graphics disabled. Runs just fine. But NO external display support any more.
2010 model:
I have discontinued use of gfxCardStatus to solve the MBP kernel panic problem as the issue is better solved on 2010 models with the nVidia GPU by the following hack:
https://github.com/julian-poidevin/MBPMid2010_GPUFix.
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There is a completely different hack developed by dosdude in his hacking of installing Sierra, High Sierra, and Mojave on unsupported Mac Models. It requires only single-User mode to get started, then type a complicated string into NVRAM, then disable System Integrity Protection and run an additional little program (direct-download link provided there) to make the change semi-permanent.
http://dosdude1.com/gpudisable/
