A Raspberry Pi 4B by itself is very easy to fit in - it just replaces the existing Raspberry Pi 3B and can have all the connections the same.
If you mean putting in a Navigator as well (in place of the Pixhawk) then I’d direct you to this comment
A Raspberry Pi 4B by itself is very easy to fit in - it just replaces the existing Raspberry Pi 3B and can have all the connections the same.
If you mean putting in a Navigator as well (in place of the Pixhawk) then I’d direct you to this comment