Buttons not working - USB works

[Flavor]

Thx for your help again. Still not working. :/
Do you have another idea?

The output that you showed seems to suggest that all of the commands worked properly. Even at the end, it says, "DKMS: install completed" without showing any errors.

There is a bit about "rmdir: failed to remove '': No such file or directory" which seems a bit off, but I'm not sure.

After you did all that, did you reboot the machine? After you reboot, could you please tell me the output from these commands?

ls -la /dev/input
dmesg | grep mk_arcade
dmesg | grep js
/etc/modprobe.d/mk_arcade_joystick.conf
sudo modprobe -r mk_arcade_joystick_rpi
sudo modprobe mk_arcade_joystick_rpi

Also, this next command should allow you to test the joystick.

jstest /dev/input/js0

After that, if we still can't figure it out, the next step may be to make an image of your SD card and send it to me. Debugging this remotely is proving to be quite tough, I think. Typically the dkms build/install just works.