Pues podias poner aqui el programa ese pa reventar el PAK e igual te podiamos ayudar
Yo por ahi he leido esto:
1. extract ISO using ISOBUSTER on HDD.
2. dummy all files in PSP_GAME\USRDIR\MOVIES with zerobyte ones.
3. start up the ExPERT Tool.
4. select psp_Pursuit_Force_4_pak.epi under "Plugins"
5. select all.pak under "Big File"
6. extract lba table under "Extractor".
7. extract file under "Extractor".
8. Quit Expert Tool.
8. goto new created folder: PSP_GAME\USRDIR\@ALL.PAK\Data\Sounds\Speech\
9. dummy everything with zerobyte files that does not have _en or _EN at the end if filename
10. start expert tool again.
11. select psp_Pursuit_Force_4_pak.epi under "Plugins" again.
12. select all.pak under "Big File" again.
13. click on Rebuild File under Rebuilder.
14. delete
@ALL.PAK folder and any other data that is not needed anymore.
15. build iso using umdgen.
16. hopefully it should work now.