Loading older versions of APM FC Firmware

Been having some issues with my MINIM OSD (‘No Mav Data!’ message) and was going to try the suggested downloading of an older version firmware to the FC.

However I can’t seem to be able to identify how this is done through APM Planner?

I knew this was pretty easy in Mission Planner but I’ve only got easy access to a MAC (and APM Planner) at the moment.

Thanks for any assistance!

If you click File->Advanced Mode, you will see a “Custom” button that will allow you to select a file to upload:
i.imgur.com/IzyHvcG.png

Old versions of firmware are available here: firmware.diydrones.com/