1st: Take a Look at your Game, how much GIL you have, WRITE it on a Sheet.
2nd: Copy your Save to USB, open it on PC with HORIZON by DoubleCklick you Savefile, than go to CONTENT, rightclick & extract.
3rd: Open the Jappi-Decrypter & save the Decrypted File where ever you want.
4th: Open the decryptet File in HxD Editor & choose "Surch"..choose "Integer Number" (& under the "any bitwith" is any to choose, so choose the 2nd in it).
5th: now type in the written GIL (when u have 900Gil, you come at 4Hex-Scince). (to mod your Gil well, only mod 8hex-scince)
6th: Begin to "mark" the 2hex before the one you found, only 8 Hex enpugh & rightclick on that what you mark & select "select block" & choose "DEC" & type in the "Lenght" 99999999, after type in, choose "Hex" copy that hex wich are choosed from 99999999 and press STRG+V. Than press Chancel on the Window, so it closed.
7th: Now go to the 1st 2 Hex, wich you have choosed to start before and press "STRG+B".
8th: Press Strg+S (this will save your file) & close the HxD Editor & open the "decrypter" open your decrypted File & encrypt.
9th: Put your modded File to your USB & to your Xbox or Ps3 and have fun.
Or u use "Bruteforce Save Data". (thats the easy way for PS3).
http://www.youtube.com/watch?v=5cWp7bnXlNs