
If updating to Catalina, let the CatalinaOTAswufix run.Using the refind-install script from the binary zip file should be all you need. However, I’ve found that installing rEFInd via a Linux session works just as well. The proper installation is demonstrated by this youtube video: rEFInd: How to Install and Boot Alternative OS on Mac. The file you want is the binary zip file found on the getting rEFInd from Sourceforge page via the rodsbooks website. The Catalina Patcher will allow the creation of install media (19H2) and the CatalinaOTAswufix will allow update to the latest version (19H524) after installation. Thread from macrumors: Catalina on Unsupported Macs.

Links to run macOS Catalina on your Unsupported Mac: If you are going to dual boot / repartition you might as well bring that unsupported macBook up to a currently supported OS.

Personally I would not dual boot and just run Linux on that old mac but…
