If the background check yields positive results, look up your router model on the DD-WRT website's wiki, and grab whatever files are essential for completing the modifications that you'll need to make. You'll probably have to download a couple of firmware files: an initial "mini" version that installs basic functionality; and a final, full-featured version. For the Asus RT-N16 router that we used for our project, we needed both the mini and the full-size files.

At this point, some warnings are in order. First, as noted earlier, installing firmware on routers is not a universal process. You can update some routers via a simple file upload; others require elaborate, multistep procedures. Second, as also noted earlier, you should search for and read any information relevant to your particular router model in the DD-WRT wiki and forum. Third, before starting, you should investigate and learn about any potential recovery procedures for your particular router, in case problems arise. And finally, you should use a hardwired ethernet connection to perform all of the router modifications that we discuss in this article; don't attempt to flash firmware over a wireless connection.

Now we're ready to walk through the process of installing DD-WRT open-source firmware on an wireless N300 gigabit router. These steps probably won't exactly match those for your router, but typically the steps do entail resetting the router to factory defaults, flashing an initial mini build of DD-WRT, resetting the router again, and then flashing the final or upgraded build of DD-WRT.

1. Clear NVRAM and restore factory defaults: Assuming that you've already downloaded the required firmware files, you now need to clear the router's NVRAM (where any nonfactory-default settings are stored) and restore the unit's factory defaults. Doing so will minimize the likelihood that a problem will arise during the initial phase of installation.