I'm running 2.7.1 (Mavlink 1.0) on an APM1.4. Just turned on the MinimOSD with the 3DR (900mhz) radio at the same time. The OSD comes up, but with no data (e.g. 0 degrees on the heading). 3DR radio works fine. I left the TX line off the MinimOSD connector, as per the wiki. This setup worked with Mavlink 0.9.
As a test, I disconnected the 3DR radio connector and took the TX line out of the connector and put it in the MinimOSD connector and the OSD worked fine.
I'm wondering if the serial port oilpan driver cannot handle two loads???
Has anyone seen (or know about ) this issue??