Skyviper Journey Serial

Hi, I have a Skyviper Journey model with Ardupilot, and I would like to replace the sonix video streaming board that is connected over serial with a Raspberry pi, if possible. I have removed the board, and tried interfacing with the serial pins it was connected to in a number of ways, using a USB with Mission Planner, as well as straight to a RPi with mavproxy. In both cases, I was unable to get a connection to work. As far as I understand, the Sonix Board is communicating with MavLink 2 at 625000 baud, shouldn’t any serial device I use be able to use the same protocol to communicate with the FC?

Thanks!

Your understanding seems correct. This post explains it in detail: Using the SkyViper Sonix board with any Pixhawk