I have a WGR614L and I tried the recommended way to install it, i.e. have a 30-30-30 reset first. However, after flashing with the .chk file, the router would on reboot sit there with the power lamp flashing. Fortunately it was possible to restore the official firmware through tftp. In my view, this article should be headed by a fat "Don't use this, use XXX instead"