I apologise for bumping the absolute oldest thread in this section, but I'm researching this very topic.
I'm trying to find information on PSO's patching packets, and since Sega never used the patching function themselves, the only working implementations are in these programs for using PSO to boot homebrew on the GC. Sadly, none of them are open source, but I found an interesting reference on GC-Linux.org's page for
psolore:
Indeed, there is already at least one PSOload-like clone with source code available (but with no reloading feature).
Does anybody know what this clone was called, who wrote it, or where I might find it? It sounds like the best way to learn about the patching feature outside of logging packets when using PSOLoad or PSUL.