@TheNoLifeKing You must zip the Payload folder and rename the Payload.zip with .ipa as an extension… You can rename it RetroArch.ipa for example!
Looks like i’m already using core v1.0 so there isn’t anything more i can do at the moment
Did this ever got fixed? Having the same prob. No errors in Provenance emulator so somehow they got it fixed 
Any chance you can share your compiled .dylib? Want to test out this Mupen core on macOS, but I can’t find it on the platform.