For what it is worth, there is a Youtube video (in Russian) about updating firmware:
https://www.youtube.com/watch?v=LmLSmJku3oc
Firmware seems to be downloaded from:
(
http://wexler.ru/support/download-center/
Hopefully not in Russian only, but even that would probably be an improvement on your current position.
It looks like an interesting reader. Good luck.