Linux-libre does not support any device which has code that depends on
non-free bits. If there is something that is in the code that is non-free it
is a bug. It shouldn't be there and will be removed.
The only 802.11n wifi chipsets for mini/pci/pcie devices compatible with
linux-libre are Atheros and I think there is limited support for one broadcom
chipset.
The only 802.11n USB wifi chipsets compatible with linux-libre are from
Atheros.
The only 802.11g usb wifi chipsets compatible with linux-libre are from
Realtek.
It is not necessarily all of any of these chipsets are fre software friendly
though. But there are at least a few from each. Not unsurprisingly these are
the best supported wifi chipsets in GNU/Linux regardless of the the
distribution being 100% free or not. That means these also work the best in
distributions like Ubuntu and Linux Mint.
