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.