Two consecutive REFRESH button presses doesn't perform refresh

[nextguyover]

Second press of Refresh button doesn't perform the image refresh as it should. Seems to only be an issue when image randomisation turned on.

Currently unable to examine root cause of this issue due to lack of access to programmer (planning to do so at later date).

[nextguyover]

Due to inconsistent refresh button behaviour, assumed that auto sleep based on ADC battery measurement might be an issue (when incorrectly reading 0V values). Implemented (71049c7, 7177d4e) as stopgap measure.