I have an activation system with a unique password per activation operation. If the system goes down or is not working correctly and I need to reset it to a operational state I could design a hard reset key combination so that the system recovers. Nonetheless I would need the password to be different each time the system recovers (this was the original explanation, and is wrong) process an activation operation.(correct)
I would like to know if, during a hard reset operation, a microcontroller is capable of changing a variable, store it and use it after the hard reset operation.
The thing is that the new password should be also known by another device that is not connected to that microcontroller.
In a normal operation both devices are synced with their passwords so, maybe, if the microcontroller detects a hard reset, can the current activation password be saved in non-volatile memory before resetting and use it after reset?