I am having the same issue, my USB 2.0 Wifi device does not work on my USB 3.0 port, tried with BT5r3 and r2.
The device does work on a different pc that has USB 2.0 ports.
Where you able find a solution? my laptop does not have a single USB 2.0 port.

I readed somewhere that a workaround would be to start your workstation with the USB 2.0 device plugged in to the USB 3.0 port but this hasnt worked for me.