Since "backup .rar" files are usually shared by technicians or users who have manually dumped the firmware from a working unit, you should check specific tech forums or official support sites based on your board's version. 1. Identify Your Specific Board
Plug it into the DVR and go to Main Menu > Information > System > Upgrade (or similar path depending on your interface).
Depending on the specific brand or board model, you can often find the necessary files here:
Sites like GSM-Forum or specialized CCTV forums often host .rar or .bin backup files uploaded by community members. 3. How to Update via USB
Use a drive 16GB or smaller, formatted to FAT32 .