Recently, one of our valued PSX-SCENE members Inf1 posted a quick how-to, with his sudden discovery on a way to play some of these PS3 Games which previously had files larger then 4gb+ so they could only be backup to your internal PS3 HDD, and not played from your External FAT32 USB HDD.
It has been tested and seems to work fine with games like: Uncharted 2, Killzone 2, Front Mission Evolved1) Download http://www.chipovka.net/PSARC.zip
2) Extract zlib.net.dll and PSARC.exe to any folder
3) Find any files more than 4Gb for example: \PS3_GAME\USRDIR\build\ma in\pak22.psarc (5,596,444,529 bytes)
4) Copy pak22.psarc into zlib.net.dll and PSARC.exe directory
5) Extract pak22.psarc (just drag-n-drop pak22.psarc to PSARC.exe)
6) Now copy pak22 folder with extracted files to gamefolder: \PS3_GAME\USRDIR\build\ma in\
7) Now you can delete pak22.psarc
8) Copy PS3_GAME folder with game to your External FAT32 USB HDD: \GAMEZ\Uncharted2\
9) Use backup manager to load game, should work fine.
God of War Collection also uses this format, but it still seems to have problems when playing with the it's files being unpacked.
Our many thanks to our valued member Inf1 for sharing his wonderful fine, and please see this thread for ongoing discussion on other games that work.