Some versions of PSX2PSP allow you to point to the base file manually, though the option is hidden.
If you cannot resolve the "cannot open base.pbp" error after all these steps, consider using modern alternatives that are actively maintained and do not rely on a fragile base.pbp file. psx2psp error cannot open base.pbp
A community-updated version that fixes the path bug. Available on GitHub as psx2psp-v1.6 . It includes an embedded base template. Some versions of PSX2PSP allow you to point