Hmmm.. I tried enabling the commented out option that you said, and now yellow text appears at startup saying “Joypad #1 (USB Gamepad) configured”. No mention of gamepad 2. I did notice something by watching the video, though — There are a lot of retroarch.cfg files. I’m editing the one in opt/retropie/configs/all, is that correct?
Also, I did not previously use the controller detector like that. I actually ran it from command line. To be safe, I went ahead and ran it again — No effect. Interestingly though, when I went to map the second controller by unplugging the first controller and connecting the second controller, upon running of the setup it immediately crashed back to GUI saying that it had stored in the file “.cfg” (whereas with the first controller it saved in “USBGamepad.cfg”). It didn’t actually create a file for the second controller, I am assuming this is part of (or the source of) the problem.
Do you think that’s the issue? Is there a way to manually create a configuration file for the second controller?