Have you tried going into System Preferences, Security, Advanced (I think it's "advanced", it's at the bottom right of the screen.) There you'll find a list of drivers, or something, that you can enable. I can't be more specific than that since my mac here is under IT control, and the feature is disabled.
Yep. I make some changes that SIP would catch, but I'm mostly comfortable with the boot into Recovery -> run a script -> boot back again. It's not kext stuff, though.
And if anyone wants to know, I have to disable SIP because Apple won't let me use an eGPU on my Macbook with TB2.