As stated in Flash App, fimware 1.5 and upper implement persistent configuration (settings remain even when power is lost).
Is this feature available only on some hardware version ?
I've tried with removing batteries from an AudioMoth 1.0.0 (firmware 1.6.0) and it looses its configuration. ie. continuous red LED and 'fast' flashing green LED whens switched to Custom mode.
As I have 1.1.0 and 1.2.0 models, I will try on these hardware versions when I retrieve them.