well. i just tried this on my new 600 (crazy, i know). it was as simple as downloading the flash utility from
here, uncompressing it on my computer and starting the .bat file. it needed the 600 attached (but no library manager running). it asked my language, flashed my 600, and rebooted it. there weren't any viruses (and being an IT guy, i checked) or anything else nasty in the archive.
now i have a clock in the lower right corner (
very useful) and it replaced dutch with russian. since i don't read russian, nor dutch, it's a wash.
if i want to go back to the official sony firmware i guess i'd just run their updater.
the only downside i can think of, is since the clock is running, it's going to keep updating the screen every minute, draining the battery faster.
update it doesn't drain the battery any faster, the clock only updates when the page is refreshed by you (turning pages, menus, etc). so no extra battery drain, but also no auto-update of clock.
there are two warnings..
first is make sure your reader is fully charged before attempting the flash.
second is that the eBook Library application won't work unless it also has been "russianified", you can download that version
here.
i've just tested the flashed 600 with the non-russianified reader (3.0.01.10191) and it seems to have no problems at all. i can transfer media back and forth.