This device is listed in h-node as not working: http://h-node.org/wifi/view/en/133/Ralink-corp--RT3090-Wireless-802-11n-1T-1R-PCIe
However, it was tested with Trisquel 5.5. Can you please test it with Trisquel 6.0 (and use the latest Linux-libre as lembas suggested) and report the results to h-node?
