Hey @DogEars, sorry for the delay! If it's saying "Zumi can't wake up" that sounds like the SD card may need to be re-flashed. When you say you flashed the latest firmware, are you flashing it from your computer, or do you mean a regular update?
Either way, I'll shoot you an e-mail to coordinate mailing you a replacement SD card. Meanwhile, if you could send the SD card you have so we can figure out what's going on for future cases, that'd be great.