Hi @MaxBuzz,
Thanks for testing 4.2 and reporting back. Any chance you could provide an onboard log? Ideally one for the working 4.1 and the not-working 4.2.
The MinimOSD uses mavlink so my first guess is that the SERIALx_BAUD or SERIALx_PROTOCOL (where “x” is the serial/telemetry port connected to the MinimOSD) has changed for some reason.
I’ve added this to the 4.2 issues list.
Update: as highlighted on this other thread, the issue must be the change to when AP starts using MAVLink2. Could you try setting SERIALx_PROTOCOL = 1 for the serial port connected to the MinimOSD?