As we all well know, MODE4 is not selectable and nor is custom mode. You know what, let's fix this for Avata 2. I'm modifying a Controller 3 below.

Open the controller and see that when going from controller 2 to 3 we've  lost quite a bit of heat generating chips and one battery. There is one  screw that has hot glue on top of it, I guess to detect tampering. This  is different from 2, but there still hare four screws keeping the controller 3 closed.


First you need to pry out the dark grey plastic piece at the top, then you can start to slowly pry with plastic tools the controller open. I used the iFixit toolkit accessories to accomplish this.





Take a good look around and see that the hall sensor wires are actually quite long, let's take one off and see what we can do:




Oh man, "how convenient", we can just swap the hall sensors between the sticks:




Then we can reassemble:



You will get a stick error on your next boot up, but a calibration will fix that. While calibrating you can verify that your horizontal left and right sticks have changed sides and now we finally have mode4 available.

I'm amazed how cheap this thing is inside considering the price. And why o why after several years we still do not have a software option to turn on mode4? At least with this you have relatively easy, non-destructive and reversable way to get mode4 to work on your Avata2/Controller 3 today.

As this is pretty much a PSA, a light bump for new users.

really weird that after all the requests for Avata 1, DJI did not put mode 4 in via setting in the software...

I agree, I can't understand what is the reasoning behind this. Really shows how much the admin/mod messages of "we'll communicate this to the dev team" in reality means.