It is only for games from Japan, yes. Let me be clear. I have a copy of UM from here (Japan), but using CFW I can switch between two save files. One is in JPN language and the other is in ENG. I currently don't have a US copy as my family hasn't sent it to me. The ENG file is so I can play through the game and do stuff now without having to wait until Christmas to enjoy it. (Also I can then redeem Japanese Events in JPN and ENG, assuming I have enough codes.)
Are you sure? That would be lovely, I would super appreciate it! c: