How can I downgrade the OpenEmu core for Mupen64Plus?

I have an older Mac with Intel HD graphics. I have the same issues described in this OpenEmu issue, where Nintendo 64 games, which worked fine in earlier versions of OpenEmu, are now having performance issues, running slowly with choppy audio.

This OpenEmu Mupen64Plus core issue indicates that downgrading the Mupen64Plus core from 2.5.4 to 2.5.3 resolves the problem. How can I do this?

Solution 1:

This procedure worked for me:

1. Download the desired version zip file from the release page of the OpenEmu Mupen64Plus core GitHub project
2. Stop OpenEmu
3. Delete the current Mupen64Plus core; for instance run the following in Terminal: rm -r ~/Library/Application\ Support/OpenEmu/Cores/Mupen64Plus.oecoreplugin/
4. Unzip the downloaded core in the same location; for instance cd ~/Library/Application\ Support/OpenEmu/Cores/ ; unzip ~/Downloads/Mupen64Plus_2.5.3.zip

I suspect OpenEmu won't and can't guarantee that it will always work to downgrade to older cores like this, but it resolved my issue completely this time.