How to flash Asus RT-AC66R or Asus RT-AC66U with DD-WRT open source

I returned from running a two week long SIP training event in Calgary to find my DD-WRT flashed Asus N-16 router had suffered a lightning strike in my absence, and was no longer functional. Not being able to survive without a router, I headed out the Best Buy to find the best DD-WRT capable router (with an AC radio) currently available in a big box store. I ended up with the Asus RT-AC66R (also called the Asus RT-AC66U).

The Asus RT-AC66R (or RT-AC66U) supported by the DDWRT project. Available on Amazon, New Egg & BestBuy. The correct way to flash it with the DD-WRT project is as follows…

1. Plug in your Asus router. Connect your computer to a LAN port via an Ethernet cable. Once connected, navigate your browser to http://192.168.1.1 and set up your passwords as root / root
2. Look through the GUI until you find the tick box to activate telnet access
3. Telnet to the router at 192.168.1.1 (root / root) (you’ll need a telnet client for this, like PuTTy)
4. Type mtd-erase -d nvram after successfully issuing this command, unplug the router, count 10, then plug it back in
5. Download Brainlayer’s latest DD-WRT build. This will get you a stable DD-WRT flash to work from, but does not include an AC radio driver. Find it here ftp://ftp.dd-wrt.com/others/eko/BrainSlayer-V24-preSP2/2014/06-23-2014-r24461/asus-rt-ac66u/
6. Repeat steps 1-3, the only difference is that now the GUI will be a DD-WRT GUI (not Asus)
7. After you telnet into your DD-WRT flashed router, type erase nvram
8. Unplug the router, count 10, then plug it back in
9. Now Download KONG’s latest build. He is a participant and collaborator in the DD-WRT project, but seems to often puts out builds more quickly and often with more features. The build we’re looking for is available here… http://www.desipro.de/ddwrt/K3-AC/
10. Now log into the DD-WRT GUI, and upgrade the firmware using the KONG build from step 9
11. One last time, repeat steps 1-3, then steps 7 & 8
12. Congrats! Your $130 AC router now is upgraded with the latest DD-WRT KONG build. In wireless you’ll see a 2.4 and 5 GHz wireless bands. Haven’t tested throughput speeds yet, but I have been able to connect to both.

Be sure to let me know if you run into any snags, or need clarification of any steps. Always happy to help!