Hey, well done!
And thanks for posting an update.
A couple of minor comments, for others info :
The configured IP address in the normally running state is not connected to the value the camera uses when probing for the Hikvision
tftp updater.
The probe is done using an IP address that is set in the environment variables of the bootloader.
Interesting.
Normally when the Hikvision tftp updater is first started, there is a Windows firewall popup to request allowed inbound access to the tftpserve.exe program.
Clicking 'OK' implicitly creates the inbound firewall rule.
Do you remember if you got this popup?