Buy a board or a adapter (hardware DRMs may prevent the Wifi board to be replaced) at http://libre.thinkpenguin.com (using this link, 25% of the profits on the purchase are donated to the Trisquel project) or at http://tehnoetic.com ; the only two vendors that guarantee that the hardware they sell work with Linux-libre; Buy a second hand board/adapter whose vendor indicates the actual chipset and that you Linux-libre supports (AR9271 for instance); Know somebody that recently bought a board/adapter that works with Linux-libre (not just "Linux"), buy the same and hope the chipset has not changed in between (with shops that buy large amounts at once and the probability is even lower).
There is http://h-node.org ... and it is not perfect. What matters for
Linux-libre's support is the chipset. And it is never indicated on the
wrapping because a same model can have its chipset changed during its market
lifetime and the manufacturers do not want to change the wrapping. In the end
the only reliable solutions are:
