We use Viola Plus V1.2 with Colibri iMX6 with Linux.
We want to use an USB device inside a closed housing.
Only the USB 1 will be available from outside either as host or as client.
It is not possible to have USB1/2 on X9 extension header. On Viola USB2 is available only via X6A top and USB1 is available via X6A bottom or via X4A. Also note that there is no OTG support on Viola carrier board one can use USB1 as host via X6A bottom or as client via X4A(with assembly options). Refer Viola carrier board schematics for more information.