You need both ISOs to create the definitive "v2" patched version. The patcher combines the content of both discs into a single, seamless game experience.
While the PSP has hardware limitations, the v2 patch includes tweaks to the ISO’s underlying data structure. Experienced players note faster loading times between the world map and combat zones, as well as less frequent slowdown during massive magical spells like "Meteor" or "Ultima." final fantasy type0 psp english patched v2 iso best
The opening line still hits hardest: "Are you prepared to... graduate?" Report: Final Fantasy Type-0 (PSP) – English Patched v2