The USB-Subsystem is compatible with the Lightning SW with
one extension: The "USB-Chip" in Suska has a 4 port Root-Hub
where the real HW has only 2.
3 of them are on connectors (2 at the back and 1 internally
to be used for a picoWifi). With the original Lightning drivers
only the 2 ports at the back will work.

The drivers installed on the delivered SD-Card handle all ports.
The Souces for the 4-Port-Lightning 
can be found here: https://github.com/umatthe/freemint/tree/USB1164
They detect the special ISP1164 Chip and will work with normal
Lightning HW too. 
We will try to put our extensions to the offical freemint github later.