Ending up with a working device seems unnatural... I might need to fix it until it's broken...!

So, future enhancements:

• I could reduce the size of the side GUI buttons a bit and then increase the width of the frame. The GUI layouts are defined in xml files so fairly easy to play with, but the '1010' width is hardcoded in quite a few places throughout the sdvcam binary. Probably more work than it's worth, would only gain a few pixels.
• Day/night mode doesn't seem too reliable. Or rather, it's broken. Not sure if this is a phone problem or device problem (the phone settings indicate that it should be set by the phone, but...). This might be resolved by a future update anyway, or I could just live with dark 'night' mode all the time.
• Really, the main work now is to write an android/AAuto app for my phone to display some information from the bike and various sensors. That sounds like a separate project to me...
• Only other thing I can think of is that it would be nice to get rid of the microSD card. This would mean building a new firmware image with the changed settings and binary and reflashing, but I'm not confident about a) flashing anything to that flash chip (nothing should go wrong, but there's definitely the potential to brick it) or b) building a working firmware image - the output from binwalk was such a mess I can't see it putting it all back together again successfully... I have the changed binary backed up, and microSD cards are cheap if a replacement is ever needed...