I have this same issue popping up with lots of my borons. After I flash any code (including going back to Tinker) when the device restarts or I unplug USB and plug it back in the main RGB LED flashes white once and then the device turns off.
Reset does nothing, all I can do is hold the mode button down and get them into DFU.
With a battery connected it makes it further, tries to connect flashing green for a couple seconds, then resets and flashes white, and starts over.
We want to switch our product from electrons to borons, but keep running into issues.
I found that it works fine if I connect a battery to it, not sure why.
Sounds like a power supply problem. What is your USB source?
I see the same thing on Borons that I've used for Solar Testing.
I believe some of the PMIC settings are "sticky".
Mainly, if you change the
InputVoltageLimit to 5080, some USB ports have trouble maintaining 5.08 Volts after a long/thin USB cable.
Lowering that value, or resetting to default settings would help (if that's the case for you).
Well I was wrong, connecting the battery only fixed a couple of them. I still have others that plugging in the battery just changes the behavior. One goes into listening mode (Blue blinking) and the other blinks white at the same speed.
A 2 amp USB gives me the same behavior, and the voltage under load is 5.16.
The two not working currently have been solar charging. The PMIC issues are driving me insane, I wonder why they didn’t just keep it like the Electron, that seemed very stable and I never had any power issues there.