Firmware v1.21

• Fixes a reset that could happen mid-ride. When the screen refreshed at
  the same moment the device dropped into its power-saving sleep, the
  device could lock up and restart.
• The frontlight is now held fully off while the device is powered off.
• Battery drain while powered off is still being tracked down. This
  version leaves the screen, GPS and mesh radio connections in a clean
  state for power-off, and powering off takes several seconds longer for
  now: the device measures its own power draw on the way down so the
  remaining drain can be found.

Built from f555747. Flash it from the app (Settings > Firmware), the project site, or drop firmware.bin on the SD card.