So, after lots of error searching yesterday I arrived at my problem with the OSD and it turned out it was no problem with the OSD, it was the revo.
The problem:
OSD connected on Flexi port recieves no telemetry updates.(horizon frozen, etc.)
Unless: I plug in USB from a computer with GCS running to revo OR establish an oplink connection to GCS, in both case making the revo start updating telemetry to GCS and in turn also starts updating it on Rx/Tx to the OSD on the Flexi port.
Is there some some simple solution? have I forgotten a keepalive switch for the revo telemetry somewhere or do I have to find some weirder solution like somehow tricking the revo into "there is a connection running with GCS"?