First let me say, Rockbox is a great thing! My H10 would be useless without it. I've now outfitted my whole family with H10s running Rockbox. Thanks to everyone for all the great work.
I just installed version 3.9 and tried the Upside Down display setting for the first time. (I'm running the ipodVOL skin - I like it because it's uncluttered and easy to read.) It works fine while connected to power, but if I run it on battery and let the display turn itself off, then wait a minute or so and turn the display back on, the readout becomes upside down AND backwards, with pixels smearing along the right side. Sometimes this doesn't happen until the next song starts.
I don't know if this is a new problem because I never tried it before. Any ideas?