While the average consumer and SMB class router these days is quite powerful, their full potential is usually heavily limited by the stock firmware installed by manufacturers.  While limiting available options by collecting them behind an ‘advanced’ section is an excellent idea for guiding the Joe User, cutting advanced feature access out altogether is a disservice to the more technically savvy.  Why provide high capability devices at all if they are only going to hamstrung out of the starting gate by the stock firmware’s GUI?

  1. DD-WRT – What is it?
  2. ASUS RT-N66U – Why choose this router?
  3. Which DD-WRT Version to use with the RT-N66U
  4. Installing DD-WRT on the RT-N66U

DD-WRT – What is it?

DD-WRTFortunately the open source and hardware hacking crowd long ago took an interest in unlocking the full potential of the devices they were buying, with one of the results being the alternative router firmware DD-WRT.  DD-WRT unlocks a router’s full capabilities and adds an enormous number of features generally not included by manufacturers in stock firmware.  As a further bonus, it basically standardizes the user experience across multiple devices and brands so that any knowledge and skills a person acquires with DD-WRT are instantly transferable to any new device … no more having to fumble through manuals, FAQs and the router GUI on a newly acquired device to try and figure out just what the manufacturer has decided the hip new term for port forwarding is this season and where exactly they’re hiding it in the GUI!

ASUS RT-N66U – Why choose this router?

Besides having a great nickname derived from it’s stylish look – ‘The Dark Knight’ – the RT-N66U has a lot of pros:ASUS RT-N66U Dark Knight

  • ASUS promotes the use of DD-WRT on its routers by power users.
  • Price point and availability.  Can be found for under $100 at most online and brick-and-mortar retailers, such as Amazon.com.
  • Spectacular range for both the 5GHz and 2.4GHz bands, with excellent performance for 5GHz and average for 2.4GHz.  If an attached device can support dual bands, speeds of up to 900 Mbps are attainable.
  • Gigabit speeds for both the WAN and LAN ports.
  • Two USB ports, with the idea of using one for a printer and one for network attached storage such as a USB hard drive.  This will also support USB cellular network wireless dongles.

There is a complete specifications list on the ASUS website product page as well as a user manual.

Which DD-WRT Version to use with the RT-N66U

Choosing the correct DD-WRT build and version to install is unfortunately something of an arcane art, as the rate of development on DD-WRT is very fast and so documentation is out of date very quickly or simply not kept up at all.  While the DD-WRT site advises users to find forum threads related to their router make and model to inform their decision, most of the posts assume a lot of pre-existing knowledge on the reader’s part.  Worse, much of the advice is contradictory, even in the official and stickied threads (for instance, it is often harped on that using the most recent build is a bad idea… but most of the time the builds cited in the wiki articles are hopelessly out of date and many threads contain posts recommending that the latest builds be used).

Currently the recommended firmware is the Broadcom chipset K3.X build, version 27360, tailored to the RT-N66U.  The FTP site changes structure regularly, but as of the date of this post this build is available at ftp://ftp.dd-wrt.com/betas/2015/06-18-2015-r27360/broadcom_K3X/dd-wrt.v24-27360_NEWD-2_K3.x-big-RT-N66U.trx (this is the “big” feature set; there is also the “mega” feature set, which counter-intuitively has fewer features than “big”; as randy909 has pointed out, unless there is a compelling reason otherwise it is advisable to install the “mega” version as the listed feature set lists may not be accurate and “mega” should provide the broadest coverage).  Installation information can be found on the RT-N66U wiki page, and fresh information on the latest versions and general problems can be found on the RT-N66U forum thread.

Installing DD-WRT on the RT-N66U

Thanks to hard work on the part of the DD-WRT developers, this is an easy and straightforward process (the confusing wiki page not withstanding).

  1. Download the firmware of your choice to a PC that will be attached to the router.
  2. Clear the router’s firmware settings repository (NVRAM) using the 30-30-30 hard reset method:
    1. With the unit powered on and booted up, hold down the reset button for 30 seconds (or more).
    2. Without releasing the reset button, unplug or power off the unit for a further 30 seconds (or more).
    3. Without releasing the reset button, plug in / power on the unit and continue holding down the reset button for a further 30 seconds (or more).
  3. Attached the PC to the ASUS RT-N66U via ethernet cable to a LAN port.
  4. Use the Update/Upgrade/whatever tool in the web GUI of either the stock or DD-WRT firmware to upload the chosen firmware.
  5. Wait for the router to reboot after the upload. This may take 10-15 minutes (6 minutes for the unit used for this article).  If the web GUI can be accessed via a browser, then the device is rebooted.
  6. Perform another 30-30-30 hard reset, to ensure no artefacts remain from the old firmware or the new firmware flashing process.  Wait until the router is fully rebooted.  Router is now DD-WRT flashed and ready to go!If “Telnet Management” or “SSH Management” is enabled from the DD-WRT “Administration” section, it is much easier to erase NVRAM:
    1. Telnet/SSH to your router (default IP is
    2. Log in with username “root” and whatever password was set in the web GUI.
    3. Enter the command “erase nvram” followed by “reboot”.

That’s all there is to it – your router now has a wealth of features available to explore.

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