Let me summarize the situation as I understand it.
dCS DACs are USB Class 1 and 2 compliant
For full compatibility with Apple devices, MFI certification is needed
dCS DACs are not MFI certified
So one is left with solutions that ‘happen to work’, but are not guaranteed to.
So far so good. In that case, can anyone point me to such a solution that I might try. I have tried putting a USB 3 hub between the iPad and the Rossini, but that did not help.
There is anecdotal evidence from @aublumberg that going from iPad to Bartok works