If you receive your NVR with version 2.5 or later, you can upgrade your NVR from online.
Here is how to,
1. Keep your NVR connected to Internet and make sure status is ONLINE.
2. In NVR's main menu - System setting - System Admin - System upgrade. Do the online upgrade.
If your NVR's version is older than version 2.5, you will need to download correct firmware and upgrade your NVR with an USB thumb drive. After it's upgraded, you will obtain online upgrade fearure eversince.
Here is how to do local upgrade for your NVR,
1.Find your NVR model # on the bottom label, download correct firmware for your NVR. Find your NVR model # on the bottom label.
2.Use an USB flash disk, copy the firmware to the root directory of the USB drive.
3. Plug USB disk to the NVR's USB port. Go to NVR's main menu - System setting - System admin - system upgrade. Upgrade the system from USB device.
4.When you upgrade, you should choose upgrade from USB device and for the "System". (As shown in picture below)