Comment 4 for bug 782752

Uneducated guess:

this seems to be a RT3072 chip - I believe natty is the first release where these devices are supported by the mainline rt2x00 driver (previously they used the one in staging).
The regression comes from the fact that the staging driver uses specific firmware files (rt2870, rt3070, rt3071) for each chip, whereas the mainline driver requires a "one-in-all" version of the rt2870 firmware. So natty needs an updated rt2870.bin file that contains the necessary firmware for RT3072 (and others).

The most recent version seems to be v29, available in the upstream linux-firmware repo.

(the same issue was reported in #14 of bug 580926)