It's not recommended to tftp using the POE on the NVR, just get yourself a $10 mini desktop switch from Ebay and a 12v psu, most people have one kicking around lol, and 1 patch lead.
Then your have all what you need to tftp to your camera safely.
Another option is to use your router, just unplug it and take it where you need it as it doesn't need Web access to when tftp is being done.
Then your have all what you need to tftp to your camera safely.
Another option is to use your router, just unplug it and take it where you need it as it doesn't need Web access to when tftp is being done.