I dont think it pssoble to flash it both on at the same time with firmware either. Like bad boy said, you probably will have to flash the one (eg chinese) with firmware and then flash it into the directory for the other one (eg Japanese). These language files are available to download off the internet, just look around. The directory where you must flash it to is also all over the net (sorry! im just to lazy to find the list of directories on my pc =P and i cant really remember it off my head).