Since Blackberry is essentially dead in Japan, I face a pesky challenge of getting Japanese text input to work on Blackberries I receive from our head office. Unfortunately, several other guides on the web explaining how to manually install BB firmware are out of date and no longer work. To make matters worse, the Blackberry Desktop software keeps refusing to use the BB firmware I downloaded and installed.
I think I finally figured it out...
* Install the firmware file downloaded from Blackberry's website: http://us.blackberry.com/support/apps-and-software/desktop-and-device-download-sites.html If you need Japanese text input support, look for the one with "J" in the filename. If a "J" version is not available, then download and install one from an Asian mobile provider (e.g. Singapore / HK provider) and copy the installed files/folders over the firmware installation for your mobile provider.
* Delete the vendor.xml file in C:\Users\USERNAME\AppData\Roaming\Research In Motion\Blackberry\Loader XML. This is the step that took a bit of research because this path is different from the one reported in older guides.
* Use AppLoader (not the Blackberry Desktop software) to install the new firmware. It can be found at C:\Program Files\Common Files\Research In Motion\AppLoader\Loader.exe.