First try Yum clean all and see if that helps.
You can get your list of packages like,
rpm -qa --qf "%{NAME}\n" > packages.lst
Unlock everything in \usr and move \usr \etc and \var out of the way.
Run
https://repos.arcanoae.com/anpm/pentium4/rpm-yum-base-os2-pentium4-2025-11-22.exe in the root of your system.
Reboot.
Mount your ISO, to quote Lewis,
Mount the latest ArcaOS ISO, ensuring that the letter matches the path
rewriter setting (or change the path rewriter setting to match the
letter assigned for ISODrive).
This to get the ArcaOS RPMs that were installed during the original install.
Install findutils RPM for xargs,
run
xargs yum --skip-broken -y install < packages.lst 2>&1 | tee packages.lst.log
Some packages may fail due to dependencies and need installing after.
This is actually based on Lewis's experiments to upgrade i686 to P4, which I did a week or so back.