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RT-N66U 1.jpg
Wireless-N900 Dual-Band Gigabit Router
RT-N66U 3.jpg
Dark Knight Double 450Mbps Dual N Band Router
3rd Party Firmware
Tomato any flavor
Status Unknown
Brand • Model • Rev
Serial Num. Prefix
wireless router
Broadcom BCM4706
CPU1 Type
CPU1 Speed
600 MHz
Flash1 Chip
Spansion S29GL256P10TFI01
Flash1 Size
32 MiB
33,554,432 B
262,144 Kib
32,768 KiB
256 Mib
RAM1 Size
256 MiB
268,435,456 B
2,097,152 Kib
262,144 KiB
2,048 Mib
RAM1 Chip
Samsung K4T1G164QF x 2
nvram Size
ETH chip1
Broadcom BCM4706
Broadcom BCM53125
Ethernet Port Count
Ethernet interface OUI
08:60:6E, 30:85:A9, 50:46:5D, C8:60:00
Stock FW OS
Expansion IF types
USB 2.0, MicroSD Card slot
USB ports
SD/MMC Slots
USB Hub Compatible
19 VDC, 1.58 A
Connector type
Serial Port
x 1, 4-pin header (?,?,?,?,?)
x 1, 10-pin header
Default IP address
Default login user
Default login password
Default SSID
3rd Party Firmware Support
AsusWRT-Merlin • Wiki • (List), TomatoUSB • (List), Tomato RAF (Victek) • (DLs) • (List), DD-WRT • (List), OpenWrt
Availability common
FCC approval date 07 December 2011
Release date 22 December 2011
UPC 886227037353
(UPC DB, On eBay)
Country of manuf China
Radio 1
Broadcom BCM4331
Wireless interface OUI
08:60:6E, 30:85:A9, 50:46:5D, C8:60:00
Antenna Connector Type
MIMO status
Wireless Standard
IEEE 802.11b/g/n
up to 450 Mbps
up to 54 Mbps
up to 11 Mbps
WiFi Operating Frequency
2.4 GHz
Radio 2
Broadcom BCM4331
Wireless interface OUI
08:60:6E, 30:85:A9, 50:46:5D, C8:60:00
Antenna Connector Type
MIMO status
Wireless Standard
IEEE 802.11a/n
up to 450 Mbps
up to 54 Mbps
WiFi Operating Frequency
5 GHz
 CPU1 brandRadio1 chip1 brandRadio1 chip2 brand
ASUS RT-N66UBroadcomBroadcom
ASUS RT-N66U C1BroadcomBroadcom

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

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

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

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

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

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

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

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

Model: RT-N66U C1, H/W ver B2, F/W ver
CPU: Broadcom BCM4708 (ARM); 1x USB 3.0, 1x USB 2.0
(odmpid == "RT-N66U_C1" || odmpid =="RT-AC66U_B1" || odmpid == "RT-AC1750_B1")

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 httр:// 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 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 httр://
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 Tomato

  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).

Flashing OpenWrt


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 network, share a USB printer with 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 Support


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


Hardware Modification


 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


Facts about "ASUS RT-N66U"
Availabilitycommon +
BrandASUS +
CPU1 brandBroadcom +
CPU1 clock speed600 MHz +
CPU1 modelBCM4706 +
CPU1 model/fullBCM4706;BCM4706KPBG, UG1147, P20, 172665 N1; +
Country of manufactureChina +
CurrentVDC +
DC Amperage1.58 +
DC Voltage19 +
Date of releaseDecember 22, 2011 +
Default IP address192.168.1.1 +
Default SSIDASUS + and ASUS_5G +
Default login passwordadmin +
Default login useradmin +
ETH chip1 brandBroadcom +
ETH chip1 modelBCM4706 +
ETH chip1 model/fullBCM4706;BCM4706KPBG, UG1147, P20, 172665 N1; +
Embedded system typewireless router +
Expansion IFsUSB 2.0 + and MicroSD Card slot +
FCC approval dateDecember 7, 2011 +
FCC approval year2011 +
FLA1 BrandSpansion +
FLA1 amount32 MiB (33,554,432 B, 262,144 Kib, 32,768 KiB, 256 Mib, 0.0313 GiB, 3.051758e-5 TiB) +
FLA1 amount/MiB32 +
FLA1 modelS29GL256P10TFI01 +
Global typeembedded system, wireless router +
Has FCC IDYes +
Has imagesretail +, external +, internal +, label + and fcc +
Has support page +
Has support page modelRTN66U +
Has tag lineWireless-N900 Dual-Band Gigabit Router +
IC ID3568A-RTN66U +
LAN ports4 +
LAN speed10/100/1000 +
ManufAskey +
ModelRT-N66U +
NVRAM size64 +
Page nameASUS RT-N66U +
Power connectorbarrel +
RAM1 BrandSamsung +
RAM1 ModelK4T1G164QF +
RAM1 amount256 MiB (268,435,456 B, 2,097,152 Kib, 262,144 KiB, 2,048 Mib, 0.25 GiB, 2.441406e-4 TiB) +
RAM1 amount/MiB256 +
Radio1 802dot11 protocolsbgn +
Radio1 MIMO config3x3:3 +
Radio1 antenna connectorU.FL + and RP-SMA +
Radio1 chip1 brandBroadcom +
Radio1 chip1 modelBCM4331 +
Radio2 802dot11 protocolsan +
Radio2 MIMO config3x3:3 +
Radio2 antenna connectorU.FL + and RP-SMA +
Radio2 chip1 brandBroadcom +
Radio2 chip1 modelBCM4331 +
Revision(B1) +
SDMMC slots1 +
Serial numC21A08 +
Stock bootloaderCFE +
Stock bootloader/fullCFE;; +
Stock firmware OSLinux +
Stock firmware OS/fullLinux;; +
Supported 802dot11 protocolsabgn +
Switch brandBroadcom +
Switch modelBCM53125 +
Switch model/fullBCM53125;BCM53125SKMML; +
Third party firmware supportedAsusWRT-Merlin +, TomatoUSB +, Tomato RAF (Victek) +, DD-WRT + and OpenWrt +
USB hub compatibleUntested +
USB ports2 +
WAN ports1 +
WAN speed10/100/1000 +
Year of release2011 +