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Availability: common

Manuf/OEM/ODM Askey

FCC approval date: 07 December 2011
(Est.) release date: 22 December 2011
UPC: 886227037353 (UPC DB, On eBay)
Country of manuf.: China
Serial Num. Prefix: C21A08

Amazon image

B006QB1RPY (Flag of the United States.svg, On Amazon, On CCC)

Type: wireless router

Industry Canada ID: 3568A-RTN66U

Power: 19 VDC, 1.58 A
Connector type: barrel

CPU1: Broadcom BCM4706 (600 MHz)
FLA1: 32 MiB
33,554,432 B
262,144 Kib
32,768 KiB
256 Mib
0.0313 GiB
(Spansion S29GL256P10TFI01)
RAM1: 256 MiB
268,435,456 B
2,097,152 Kib
262,144 KiB
2,048 Mib
0.25 GiB
(Samsung K4T1G164QF-BCF7 × 2)

Expansion IFs: USB 2.0, MicroSD Card slot
USB ports: 2
JTAG: yes, 10-pin header
Serial: yes, 4-pin header

WI1 chip1: Broadcom BCM4331
WI1 802dot11 protocols: bgn
WI1 MIMO config: 3x3:3
WI1 antenna connector: U.FL, RP-SMA
WI2 chip1: Broadcom BCM4331
WI2 802dot11 protocols: an
WI2 MIMO config: 3x3:3
WI2 antenna connector: U.FL, RP-SMA

ETH chip1: Broadcom BCM4706
Switch: Broadcom BCM53125
LAN speed: 10/100/1000
LAN ports: 4
WAN speed: 10/100/1000
WAN ports: 1


Stock bootloader: CFE

Stock FW OS: Linux

Third party firmware supported: AsusWRT-Merlin (List), TomatoUSB (List), Tomato RAF (Victek) (DLs) (List), OpenWrt, DD-WRT (List)

Flags: MicroSD Card slot

Default SSID: ASUS (71 addl. devices), ASUS_5G (34 addl. devices)
Default IP address:
the IP is used by 924 additional devices
of which 113 are ASUS devices
Default login user: admin
Default login password: admin
admin:admin credentials used by 881 additional devices
of which 117 are ASUS devices

802dot11 OUI: 08:60:6E (1 E, 1 W, 2011), 30:85:A9 (3 E, 3 W, 2011), 50:46:5D (2 E, 2 W, 2011), C8:60:00 (2 E, 2 W, 2011)
Ethernet OUI: 08:60:6E (1 E, 1 W, 2011), 30:85:A9 (3 E, 3 W, 2011), 50:46:5D (2 E, 2 W, 2011), C8:60:00 (2 E, 2 W, 2011)

For a list of all currently documented Broadcom chipsets with specifications, see Broadcom.

Asus RT-AC66U Dual-Band Wireless-N900 Gigabit Router

Dark Knight Double 450Mbps Dual N Band Router

Product page

Simultaneous Dual-Band, Gigabit Ethernet, 3x3:3 (450Mbps)

FCC ID: MSQ-RT0K00 - ASUS RT-N66U - PCB Rev.3.3

Annihilator666's photos have a sticker on the device showing an OUI of 10:BF:48

LAN OUI of 20:CF:30, presumably. 50:46:5D OUI

The CPU is part BCM4706KPBG. The switch is part BCM53125SKMML.

This router is sold in some locations as the RT-N66R.

It is also available in white as the RT-N66W.

Revision B2 is the same as B1, but have different CFE version.

Wi-Fi Certified (alt.) (as of 07/30/2011)

Links of Interest


Forum threads

now fully supported as of March 25



Flashing DD-WRT

Asus RT-N66U on dd-wrt wiki

NVRAM issue

As of June 2012 there is an issue with NVRAM all but being filled by the default DD-WRT installation. Until this issue is resolved, please know about the pro and cons of this issue, before you install DD-WRT on this router.

There are however frequent general news about this issue. If not daily, then weekly news. And eventually a solution to (preferably a 60/64K solution) will also reach the DD-WRT community.

As of this writing (June 30, 2012) has implemented a solution, that lives with 32k NVRAM for CFE, but extends to ~60k in firmware.

As of July 16, 2012, TomatoUSB, Shibby has implemented a 64k NVRAM solution that lives with 32K NVRAM for CFE See Flashing TomatoUSB

Principle steps

  • Clear settings (Clear NVRAM) select Factory Default settings
  • Install the INITIAL ASUS RT-N66U version of DD-WRT (file name ends in .trx) using either the Web GUI method or the Recover Utility method. Both methods are described below
  • Clear settings (Clear NVRAM) select Factory Default settings
  • "Upgrade" to your final version of DD-WRT (filename ends in .bin) using Web GUI or Recovery Utility
  • Clear settings (Clear NVRAM) select Factory Default settings
Note: is IMPORTANT to Clear NVRAM (to select Factory Default settings) BEFORE and AFTER upload of any new firmware.

Upload Firmware via Web GUI

  • Clear settings (Clear NVRAM) select Factory Default settings.
  • Upload the .trx file using the stock web GUI.
  • Wait for the router to re-boot on its own. This may easily take 10–15 minutes to happen, so just be patient.
  • Clear settings (Clear NVRAM) select Factory Default settings. Wait for the router to re-boot on its own!!! May take 10 minutes or more

Upload Firmware via Recovery Utility

  • Set your NIC card to static IP, Subnet, Default gateway (Static IP guide)
  • Put router into recovery mode by holding down the reset button while powering up the router, wait until the power led is blinking slowly, then release the reset button.
  • In the Asus Recover utility Access the router’s built in recovery mode by issuing in browser field.
  • When completed wait until the router re-boots on its own. This takes at least 10 minutes.
  • Put router into recovery mode by holding down the reset button while powering up the router, wait until the power led is blinking slowly, then release the reset button.
  • Flash the final DD-WRT build, could be any of:

Simple Instructions (Works for most)

1 Holding the reset botton with out energy cable, connect energy cable and switch on the router with the reset botton pressed till the "on" led blinks slowly.

2 Try and now you see the MiniWebserver.

alt text

3 Klick Durchsuchen und in the Fileserver search the Firmware.trx and click open.

(Click Browse and in the Fileserver search locate the Firmware.trx and click open.)

Now click Upload

alt text

4 When the firmware fully loaded click Continue.

You are back to the MiniWebServer , now click Restore default NVRAM values.

alt text

5 Now get <nowiki></nowiki> into the Browser and press Enter

alt text

6 Now click Continue and then click Reboot

7 Try and set Username and Password

alt text

If you are not fast enough and the router reboots then you can do step 1,Clear NVRAM and do step 5&6 without loading firmware again.

  • When completed wait until the router re-boots on its own. This takes at least 10 minutes.
  • Put router into recovery mode by holding down the reset button while powering up the router, wait until the power led is blinking slowly, then release the reset button.
  • Select Reset NVRAM defaults when it completes (should be quick), in the browser field, type in <nowiki></nowiki>. When done press enter. When complete select reboot and wait 5–10 minutes for the router to reboot and start building its layers.
  • Now you should be able to access via web gui and it should be DD-WRT.

Flashing TomatoUSB

shibby's Mod
toastman's Mod

  1. Set static ip address on computer of
  2. Download the file 'tomato-K26USB-1.28.RT-N5x-MIPSR2-101-AIO-64K.trx'
  3. Put the router into recovery mode by holding down the reset button in the back of the router and plug the power in. Continue holding the reset button until the power lights blinks slow, then release the reset button.
  4. Use the Asus recovery disk and upload the tomato firmware.
  5. Wait until it finish, about 5min. If you do not wait you will brick it.
  6. Power down the router
  7. Power up the router and you now have tomato on it.
  8. Reset nvram (Thorough)


Updating DD-WRT

If dd-wrt is already on the router follow these instructions. If stock firmware is on the router follow the flashing instructions.

  1. Check for recommended builds here first.
  2. Set your computer to a static IP of (or to whatever subnet the router is on) Disable all firewalls and security. Disable wireless on your computer and only have the router connected to the flashing computer by the ethernet cable between the two.
  3. Hard reset or 30/30/30 (If the router supports it, if not, reset to defults in the GUI) prior to flashing. Wait. Check for password page on re-login and change password.
  4. Flash firmware. You can use the webgui except if you have a belkin router. (For belkin use tftp.exe to flash)
  5. least three minutes. Lights should return to normal. See important2, below. Failing to wait is how most people brick their routers.
  6. Do a power cycle of the router. (Unplug the cord, count to 30 and plug it back in.)
  7. Wait for the lights to return to normal usually about 2 minutes.
  8. Hard reset or 30/30/30 again (If the router supports it, if not, reset to defults in the GUI). Wait. Check for the password page and re-login to change the password. Then you can reconfigure your settings manually.
  9. Once configured set your computer back to autoIP and autoDNS.

Important1: This Hard reset or 30/30/30 works fine for Asus router, but you do have to power cycle after the reset.

Important2: After you flash the firmware, and before you do the hard reset, the router will be building some nvram settings. YOU MUST WAIT FOR THIS TO FINISH PRIOR TO DOING ANYTHING WITH THE ROUTER INCLUDING A HARD RESET. Usually, you can tell when this process is completed by the WAN light coming on, but it does take several minutes. Go have a beer. There are starting to be more and more people who BRICK their routers by not waiting until the nvram is rebuilt, PRIOR to doing a hard reset. YOU NEED TO WAIT!

JTAG-Serial Info


RT-N66U Jtag On DD-WRT forum

JTAG Pinouts

J2 sure looks like a JTAG header

1 © nTRST |  2 ® GND
3 © TDI   |  4 ® GND
5 © TDO   |  6 ® GND
7 © TMS   |  8 ® GND
9 © TCK   | 10 ® GND


Console connection on N66U and TUMPA board On DD-WRT forum

Serial Pinouts

Serial is J1 Serial is J1

 R| VCC  1 © |F
 E|  RX  2 © |R
 A|  TX  3 © |O
 R| GND  4 © |N

USB Info


The USB port is where you can connect an external USB hard drive or flash drive. Which can do a multitude of things. You can use in as a NAS, storage for a FTP server, use Optware to run external programs like torrent software, samba for sharing files to your network, share a USB printer with your network... The list of possibilities is long, it just takes a little research.

ProFTPd is included in most the newer builds of dd-wrt. Check the features chart to be sure.


TomatoUSB comes with file sharing, ftp server and media server built in.

Tutorial: How to set up NAS and Optware on Tomato FOR TOTAL NOOBS

vlan Info

DD-WRT vlan Info

VLAN Support


Asus' RT-N66U
DarkShadow's Unit
Annihilator666's Unit


Possible 64k CFE


 sdhci: Secure Digital Host Controller Interface driver
 sdhci: Copyright(c) Pierre Ossman

After sticking in a 2GB MicroSD card and rebooting, the card is seen and mounted to /tmp/mnt/sda1

 df -h
 Filesystem                Size      Used Available Use% Mounted on
 /dev/root                17.0M     17.0M         0 100% /
 tmpfs                   124.8M    412.0K    124.4M   0% /tmp
 devfs                   124.8M         0    124.8M   0% /dev
 /dev/sda1                 1.9G     24.0K      1.9G   0% /tmp/mnt/sda1

Contents can be shared via samba in OEM firmware, now to figure out how to run custom scripts from the oem firmware.

Mounted MicroSD Card in TomatoUSB

Card was partitioned and formated in Ubuntu with GParted

Mounted MicroSD Card on TomatoUSB

On InfoDepot Moved to TechInfoDepot
Info from BrainSlayer (DD-WRT forums)
Internals and boot log on vr-zone forums
Reviewed on SmallNetBuilder

TomatoUSB (shibby) on the RT-N66U

LAN OUI of 20:CF:30, presumably. This is assumed to be a BCM4706 device.

Trouble with recovery mode


I just want to give a tip for anybody who has trouble getting into recovery mode. I didn't find this simple information on the internet yet. First, some context:

I flashed a Brainslayer build from a Fractal build, and then my router stopped responding to ping. When booting normally, the power and ethernet LEDs would light up. The same thing happened when booting up with the reset button pressed, which should have put into recovery mode, but didn't. When booting up with the WPS button pressed, the power LED would flash and clear the NVRAM. The router then started up and enabled the two radios, broadcasting a "dd-wrt" SSID, but still no ping.

To force it into recovery mode:

  1. Set a static IP of
  2. Press the WPS button and start up
  3. Let the power LED flash rapidly for 5 seconds, then release WPS
  4. Immediately press the reset button, keeping it pressed until the power LED flashes slowly
  5. Release the reset button
  6. Point your browser to


Hardware Modification