The latest ROS version where WiFi works is 7.6. And I am still forced to stay on this version. When you will fix this issue ?
A suggestion is to use CHR on Hyper-V. There is minimal overhead, and it eliminates the need to worry about chipset and device driver support, which are instead handled by the Host OS (Windows).
Closing topic as it is clone of http://forum.mikrotik.com/t/issue-atheros-ar9888-not-working/165872/7
and IMHO for not working MTK card there should be a ticket opened or/and complains should go there: http://forum.mikrotik.com/t/v7-12beta-testing-is-released/168851/1