It's always a good idea to do that anyway if you buy a device second hand, you never know what kind of weird (or even dangerous) stuff has been installed by the previous owner.

Firmware updates are so useful because they let you roll the device right back to the condition it was in when it left the factory.

Well... my proclivity is to back up the system first; that way I can snoop around, because I'm curious. But then reflash the device, of course, and do the snooping in the backup.

(It's also a very good idea to reflash before you sell it, lest someone like me in curiosity, but perhaps less scrupulous about using any personal data left in it, should buy it.)

It was probably owned by a Korean/Chinese/Japanese guy.

matchbox-keyboard is installed by default with maemo-cjk and the input method switcher which you can see in the statusbar of that image (far right)

http://maemocjk.garage.maemo.org/