I'm not sure Joe. It should work fine. If you get a different firmware from the vendor, upgrade/downgrade to that, then try again it might work. Totally up to you though!
Just wanted to say thanks to everyone who contributed to this thread. After a few weeks of trying to figure out what I was doing wrong, I stumbled across this forum and it turns out I had gotten a PAL version 5216 like Dan - which I hadn't expected. I was able to download the PAL version of the update file (from http://downloads.smartwaressecurity.com/CCTV-IP/Dahua/Firmware/NVR/NVR5208_5416/). I had to change the name of the file to update.bin (as RyanODan suggested) and was able to complete the update via USB.
The big downside to completing the upgrade is that the NTSC file (16MB) would NOT load - only the PAL version (the 23MB) would. My NVR used to have video standard set to NTSC (via a dropdown on the configuration page). Now my only option is PAL. I'm struggling with compatibility issues with Panasonic cameras and this NVR, but am still not sure if the NTSC cameras will work with the PAL NVR :sad2:
Good point jackdish - I had meant to edit my post above. At first I thought the 5216P = PAL whereas 5216N = NTSC (and that I had just ordered to wrong version). Now realize that's not the case :redface-new: