Hi
I have the obscure model 4810mq and 4k display, running web driver 10.11.4, sip disabled, and the k2100m working all great except for the internal display. I have tried SMBIOS MBA6,2 and rMBP11,2 yet none of those enable the internal display. In this model you have to use the k2100m, no hd graphics present, or optimus.
I also know that the internal display is eDP connected, it is 4k @ 60hz so had to be that. I can attach anything if needed, including ioreg files (v2.1), dsdt's, ssdt's and whatever other acpi files i got from clover f4.