First of all, thank you all for doing this great stuff. It's also great that so many friendly user are here, which try to help and made this hole thing even better I paid the double price to get a classic mini an i love it. After a few problems i have now about 200 nes and snes games and they are working great (not tested all yet).
For beginners like me i highly rrecommend the youtube videos from eta prime
I know that there are many other fantastic videos but the one frm eta prime solved my problems. The viedeos are easy and in english and he is telling basics (which are enough for me).
Perhaps i can also help some members here.
I'm using the 8Bitdo controller. It's the wireless version with four red buttons and the two shoulder buttons. I also had problems in the retroarch settings and after that, i was not able to navigate. For nes this controller is great but it doesen't work for snes.
What solved my problem:
Uninstalled the retroarch hmod from hackchi
copy a new retroarch hmod file in the correct folder
Intstall retroarch hmod again
Perhaps you don't habe to copy a new retroach ans just reinstall it. Id all of that and can now using my controller agai. I will buy another controller and a 10 feet cable ans use the 8Bitdo only for NES, maybe a PDP Wired Fight Pad for Wii U.
Sorry for that long text and for some mistakes. My english needs to grow up again
Regards from Switzerland