Cant install arducopter on Pixhawk4

whats the trick to install AC3.6 (or any) on the HolyBro Pixhawk4 FMU5 unit? tried using MP and GC and while I can install PX4 with QC, no such luck with AC3.6…MP gives me all sorts of device not recognized, etc
I know there is nothing wrong with the unit as PX4 works fine, but I want AC instead…

you’re on latest missionplanner?

correct , latest beta

Download the .hex file from here and install it with QGC. It works fine in QGC because I just flashed both my Pixhawk4 and a CUAV Pixhack V5 with it today.

I eventually used Apm planner on a Mac and it worked there… Thank you