Never mind. Found out it's the recent update to RetroArch causing the issue. Re-installing the image without updating fixes the issue.

@barbudreadmon Evo 2014: https://kotaku.com/the-2014-evo-champ-just-won-using-a-ps1-controller-1604535870

I had all sorts of issues with the ds4 using ds4drv, it caused the pi to overheat, but I didnt have any lag,
either way, I purchased the usb dongle for the ds4 and the problem was instantly gone.
for 20USD i would reccomend you dont waste your time, and just buy the dongle.

@bengdahl Did you ever find a solution for this? I'm having the exact same problem.

@WetpantsMcGee

Good to hear. Welcome to the forums btw.

@lensdrifter
Please do not post a support request without first reading and following the advice in https://retropie.org.uk/forum/topic/3/read-this-first

Anyways:
Which emulators are you using to emulate "arcade-classics"?
Which roms/"arcade-classics" you tested it with?
Which 8bitdo controller do you use?

@wack26
Pleas update RetroPie-Setup and install mupen64plus again. Keyboard should work now.

This seems the most similar to my issue I've found. What is that editor you are using for the .cfg file? Also, this wouldn't happen to be with DragonRise controllers would it?

@edmaul69 i don't have money for that and i use it in pc games fine. It's just i need an fix for the b button bug

Like a guess that you aren't using a libretto core PSX emulator.