Pixhawk2.4.8 for Rover
1.Upload the V3 firmware
Select fmuv3, NOT OTHER.
2.Download Mission planner?
the latest firmware ues MAVFTP , so you should ues the latest mission planner.
Download the latest mission planner from here, https://firmware.ap.ardupilot.org/Tools/MissionPlanner/MissionPlanner-1.3.76.msi