The meter is only in bootloader mode for 5 seconds after a reboot. Some Android devices seem to take a long time to find and connect to a peripheral, I expect this is where the difficulty was coming from.
Thanks for the report of erroneously starting the FW update activity after updating new firmware. From your description of the fix it sounds like some state is being saved in the app or in Android that needs to be updated, and restarting the app cleared it. I added it as an issue on the Mooshimeter android app github repository.
Thanks again, let me know if other issues come up.