I just upgraded my NVR and 5 x Dahua cameras with Dahua latest firmware since July 2021. One of the camers ended up with STATUS FAIL and "died". I have tried to reboot and reset it but there is no sign, the green LED on its internal PCB is dead. Upgrading these things can also be risky, Camera versions is IPC-HDW4831EM-SE, upgrading from F/W 2017 to 2021.