I've added support for NF2 and NF6 into cgminer git master branch. I'm not getting much love out of the NF6 just yet but they may well need so much power that even a regular USB3 port is not enough. The NF2s are behaving very nicely. This is at --nfu-bits 54:
14: NF2 00001099: | 4.670G / 4.655Gh/s WU: 65.2/m
23: NF2 00000753: | 4.447G / 4.509Gh/s WU: 63.6/m