I had crashes to 4% from 300 to 400 mAh charge level last week; it had been rising slow but steady during the year.

I did Makeclick's solution of letting it really run dry and then charging the phone when it was shut down. It was harder than one would assume as the phone has the tendency to try to boot up when it is connected to a charger instead of going to recharge mode. 'Shutdown -h now' as devel-su seemed to work best if it woke up unnecessarily.

I didn't pay attention to restarting part of the trick, but during three full recharge cycles I saw "the dip" move down 100 to 150 mA between every recharge, and after the third time the battery (or bme) seems to be calibrated spot on.