as stated in earlier posts on another thread: http://www.ps4news.com/forums/ps3-cf...ex-121017.html
Start there and read forward: http://www.ps4news.com/ps3-cfw-mfw/g...now-available/
but basically you have to edit the ARCHIVE and LOCALIZED ARCHIVE text files to remove the text of the files you delete. also change the number at the top of these text files to reflect the number of files listed after you deleted the ones you dont want / need.
i ripped a US copy from a friend, which had several languages other than english, but different from the EU Duplex realese , deleted all languages except english, the 2 EXTRASCIN files, and all multiplayer files and languages.
edited the text files to show the correct number and names of ONLY the files i kept, and it worked great ! was also only 20.1 GB ... hope this helps ya.