According to the OpenWRT wiki, there are three tested methods to install OpenWRT on a WD N600 router. However, when I got my hands on one, neither method worked. Every time I tried to flash the factory image (version 24.10.0 at the time), the router’s light would slowly turn on and off, as if the image was being flashed, but it would never stop. The router would get stuck and never reboot. After a couple hours of tears and frustration, I managed to figure out what the issue was. After giving the factory image a shorter name and following the wiki’s first method, the router would successfully boot into OpenWRT.

Unfortunately, after restarting it using the on/off button, OpenWRT would disappear and I would be again greeted by the “Emergency room” interface. After a couple more hours of frustration, I managed to make the factory image stay by reflashing it using the sysupgrade image, combining the first and third methods from the wiki:

1. Download the factory image and rename it to something shorter, like openwrt-24.10.0.bin.
2. Change your computer’s IP address to 192.168.1.10 and connect it to a LAN port on the router.
3. Turn off the router.
4. Use a paperclip to press and hold the reset button located on the bottom of the router. While holding the reset button, turn the router back on. Keep holding the reset button for at least 15 seconds. Wait until the power light on the front of the router starts flashing slowly.
5. Open a web browser and go to http://192.168.1.1.
6. Use the “Emergency room” interface to upload the factory image.
7. The router will take a few minutes to flash OpenWRT. Once it’s finished, go back to http://192.168.1.1 and update the firmware with the sysupgrade image.