Boron stuck in boot loop, even from DFU mode

I have a Boron stuck in a boot loop, it starts blinking green and reboots after a few seconds. Monitoring an led connected to a pin, I can see that it starts executing my software.

  • This happens also from DFU mode, where my software should not run
  • After a few tries, it sometimes stays in DFU mode
  • This happens also after flashing a software with empty setup() and loop()

The colors are a bit hard to see, but the video shows:

  • Entering DFU mode
  • Device reboots after 1s in DFU
  • Cellular connecting (blinking green)
  • Reboot (LED off, white, blinking green)

boron-bootloop

This happened on two of 4 boards with the same software. They have been working for weeks, one got in this state in the middle of the night with no one around, the other on was doing BLE communication with my pc. I can not reproduce this.
After leaving the board with the empty software without power for an hour, I turned it on and it was magically repaired. It works fine with my software since then and I tried to get it in the bootloop state again by doing over and over again what I did before, but I works fine all the time.

I found one related topic, however with no answer: Boron in Boot, Connecting, Reboot Loop

What I observed leaves me confused and I think no one can say what happend here, but while thinking about how to proceed, one question came up which at least Particle should be able to answer:

What has to happen to a board to reboot automatically from DFU mode after 1s? Which part of the software is probably damaged here?