I asked this question (or a similar question to it over on r/RG35XX/) but wanted to ask here as well. For some reason, on my RG35XXSP the menu button shuts down the system immediately. It doesn't go through the shutdown process, it simply turns the device off completely.

I installed Knulli to test it out, and honestly I prefer the stock os right now, so I went back and re-installed the stock os. However when I installed Knulli, and even now while back to the stock os, the menu button doesn't work at all like it should, and instead just shuts the whole thing down. Let's say if I were to try the menu volume rocker shortcut for brightness, that won't work, because the moment I click that menu button it's powered off.

I'm wondering if anyone else has had any issues with their menu button doing this, and if there's a way to revert it to the default usage, or re-map it somehow. It's just very weird, and after a fresh install of the stock os, it still doesn't work.

EDIT: So I saw this post and thought I might give this a try. I took apart my device and checked out the board, and sure enough it looked like the raised up rumble motor had shifted out of the circle marking on the board. The two (very fragile looking) wires connected to it were a little bent out of shape, so I slowly pushed the rumble motor back into place (although I don't know if it's going to stay there) and tried to reorient the wires a little. After I put everything back together, it looks like my menu button is working as it should again!

All in all, I'm happy I fixed it, but it's a pretty goofy workaround and if that rumble motor drifted (or was attached improperly) what's to say that it won't happen again. I also submitted a ticket to Anbernic letting them know that I had an issue with the device but I know that their support can leave a bit to be desired so for now at least it's "fixed".