when 4.66 came out then 4.66_patch <--- that's when sony added two x-platform passphase and disable sslv3 in future to can use new ssl
you need ofw dex 4.66 to compare the missing parts debug vsh but it's a shame it's not released. lol
but 4.66 rebug will be out soon hopefully.
But you could create a CEX spoofer with the VSH of a 4.66 CEX FW and a VSH of a CEX on a lower FW, right?
However I can't seem to find any more differences than the passphrase, some singstar stuff and ofc the changes in version.txt, index.dat and vsh.self regarding the fw and image version.
I feel like I'm missing something.