I just installed the newest unofficial firmware yesterday and I can already see a big change. I keep mine on standby and I would usually loose 2 bars overnight. This morning I still got all 5 bars left. So that's a huge improvement for me.
I used the zip file in the first post from
this thread on booxusers. This one doesn't change your menu to russian. It might change google and wikipedia to russian but haven't checked that.