Zymkey 'failure' after external power loss

While running a rpi 3b with a zymkey 4i fitted correctly and in production mode, I decide to try and power the unit from an external battery rather than bench PSU. I completely forgot about the rpi and returned to it the next day and found the external battery was now flat and obviously the rpi powered off.
I attached the rpi back to the PSU but found that the error “ERROR: no zymkeys installed” which is quite odd as its still in place as i left it.
Please could someone explain what has occured to cause this failure? I’ve triple checked the bench PSU and its suppling the correct voltage and current.

Many thanks


@taospartan, interesting symptoms.:thinking:

A few questions

  1. Does the zymkey have a coincell battery in it ?
  2. If yes, can you measure/communicate the voltage on that coincell battery
  3. Are you using tamper detect ?
  4. If yes, how have you armed the tamper event ? - self destruct, or notify ?
  5. What voltage & current is your bench supply deliverying?

If you prefer to go to a private communications - send to support@zymbit.com