@schnuckelpeter See if this helps:
https://forum.recalbox.com/topic/24841/8bitdo-et-recalbox

Although, I also have a recalbox, and the steps are clearly defined in this Kodi SuperRepo Tutorial, but I am unable to get it fired on the Recalbox. Are there any potential addons left in the repo?

@andré-alcover-rodrigues so you have a SEMICO USB keyboard. It has 2 possible events. You should start evtest and test bith to see which one is responding when you're typing on it. Write down its name, and find to which /dev/input/by-id it corresponds to

Next, in the moonlight.conf, simply add that /dev/inout/by-id/blablabla that worked

There's a patch file I found that fixes the problem, but how do I apply it?

Here is the patch: http://ithink.ch/blog/files/xin-mo/0001-hid-Add-new-driver-for-non-compliant-Xin-Mo-devices.patch