Is it very hard to built in a A-B repeat function?

I've searched the net for days. People both in China and Western country asking for the offical to have a new firmware which have a A-B repeat funciton in M6.

How hard do we to build this function? Can we make it ourself. Hackers over the world should have this kind of knowledge.

So far it's not even possible to install another type of firmware very easily. I think some people are attempting to build rockbox for the M6, but I don't know the status. Altering the official firmware is, I believe, completely out of the question. Apart from that, I wouldn't count on any more official firmware updates from Meizue for the M6, they need all the manpower they have on the M8.

hope hacker from all corner of the world give some contribution on this funciton.

alternative way: create folder, put 2 mp3 inside, go to browser, select folder, add to playlist, enjoy.