CNET

Mac OS X 10.3.7: Secondary volume booting problems

Mac OS X 10.3.7 may not properly boot when it is installed on a drive that is secondary at the time of installation. In other words, for some users, when Mac OS X 10.3.7 is installed to a volume other ...
CNET

Mac OS X 10.3.7 (#16): Secondary volume booting problems: Not be relegated to FireWire drives, possible explanation; more

Secondary volume booting problems: Not relegated to FireWire drives, possible explanation Yesterday we reported on an issue where Mac OS X 10.3.7 may not properly boot when it is installed on a ...
Ars Technica

Install new MacOS for dual booting? | Ars OpenForum

I got a Mac Mini several years ago that came with Catalina. I hated the new look of Big Sur, so I never installed that. I now want to install a newer MacOS (Monterey), but initially and perhaps ...