Some laptop graphics questions

I have a laptop (ASUS K501UQ) with i3 6100U/HD520 and Nvidia GPU.

1. Currently I'm failing at "Hash data from ME never returned" so I have to set -disablegfxfirmware key. What do I lose with it? It seems I still have normal graphics performance with it.
2. Whetevergreen installation guide says to remove all graphics-related SSDT. I followed Rehabman's guide to disable Nvidia GPU in DSDT/SSDT, and those edits are quite convoluted (re-disabling GPU on wake, etc.) Will Whatevergreen disable-external-gpu key do the same?