Hi Lars -
I appreciate you making the effort to at least start the process of seeing what can be released and/or documented. ADI has been nice enough to release the board schematic for the USBi but unfortunately we lack any insight in how to talk to it. The USBi has a lot of untapped potential I'd like to leverage outside the context of Sigma Studio running on Windows. Please keep me advised if you make any progress.
Thanks for your continued efforts,
Glenn