You can't flash non Router's firmware directly using Router's own web interface, because of the hardware versionb check. But you can use U-boot's web interface. Here is a simple guidance.
1. Connect your computer to the LAN port using RJ45 Ethernet cable. Leave the other port unconnected.
2. While pressing the [WIFI] button, power on the device about 5-8 seconds, then release your finger now.
3. Visit [http://192.168.1.1/upgrading.html] using your browser, you will see the Breed WEB.
Please visit our website to read in detail (with a video tutorial):