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
NFU??
Is that a question, statement, exasperation, disgust, or what?
Heh

Fun with abbreviations!
Con - I suspect he wasn't sure what the "--nfu-bits 54" part meant - which is the osc6 bits, and the "nfu..." prefix is what is used in the source code - e.g. as in this line:
mcp->value.pin[
NFU_PIN_PWR_EN0] = MCP2210_GPIO_PIN_LOW;
you would see also this in the source code:
/* Identify number of chips, and use it in device name if it can fit
* into 3 chars, otherwise use generic NFU name. */
val = sscanf(bitfury->usbdev->prod_string, "NanoFury NF%u ", &info->chips);