My name is Nikolay, I am from Ukraine, I am an engineer of a service center for the repair of security systems and access control. Faced the following problem: ZKTeco F22 ID biometric access control terminal, if communication with the server is lost, after some time (several days) it becomes unusable. The situation is the following. if the terminal is turned on, but loses connection with the server and this connection is not restored within a few days, then the terminal goes into a cyclic reboot and therefore becomes unusable. We contacted the Chinese manufacturers, they confirmed that there is such a bug in the terminal software and gave a patch that fixes it. However, the problem is that the patch can only be applied to a healthy device before it goes into a reboot loop. As a result of Russian attacks on the energy system, we had significant problems with electricity, communications and, consequently, with the Internet, in connection with this, a lot of terminals with this problem arrived at the service center. Perhaps someone has come across something similar and can advise a solution to this problem. The terminal uses NAND memory chip W25N01GVZEIT. If necessary, I can provide a memory dump of this chip from a new, working device and from a device in a cyclic reboot
All our efforts to analyze what is corrupted in the firmware of the device were unsuccessful, perhaps someone has encountered a similar problem and can suggest a solution
