Using Pico with firmware 170517. When battery gets low the Pico restarts itself. One time it was stuck in some error mode continuously firing, then restarted itself. The battery indicator had "!" sign. I tried to increase cutoff volts to 2.95 but it still crashing. Old version displayed low battery error but didn't crash. I suspect that new firmware allows voltage to drop for short period of time bellow minimum required for the board to operate.