I check this message, and got the clover install to get to a final screen but got an error of could not install on the disk, than I found this message to use a combo Catalina installer. So downloading and trying that now. Almost there!
not yet! I tried to install Catalina, got to the "macOS could not be installed on your computer". The fix is to use the 10.15.5 combo update, I downloaded, is a .dmg, what do I do now? I need to convert the .dmg or the .pkg to .app to make the new usb stick, how I do that? I am searching google but could not find a way?