Oh thats a thing were I can help :-)
My Gr12L only supports SumD and cc3d is on its way and im willing to test it!
There was a ticket about SumD at openpilot and taulabs also i think, but it seems that SumD works with nothing, so Im realy happy if it works with Librepilot!
But Iam not sure how to bring Librepilot to the cc3d, but thats another thing...
PS: revo or sparky FC is coming soon to because I realy need to get rid of the dji stuff...