ASUS RT-AC66U rev A1

From TechInfoDepot
Jump to navigationJump to search
multiple revisions of this device, use caution
abgn+ac (AC1750)
Dual-Band Wireless-AC1750 Gigabit Router (5G WiFi)
802.11ac Dual-Band Wireless-AC1750 Gigabit Router
Asus RT-AC66U 001.jpg
Asus RT-AC66U 004.jpg
3rd Party Firmware
Status Unknown
Tomato any flavor
Status Unknown
Serial number prefix
wireless router
CPU1 Type
MIPS 74K (R2)
CPU1 Speed
600 MHz 8-bit
Flash1 Chip
Samsung 216 K9F1G08U0D SCB0
Flash1 Size
128 MiB134,217,728 B <br />1,048,576 Kib <br />131,072 KiB <br />1,024 Mib <br />0.125 GiB <br /> (NAND)
Flash2 Chip
Macronix MX25L160EM21-12G
Flash2 Size
2 MiB2,097,152 B <br />16,384 Kib <br />2,048 KiB <br />16 Mib <br />0.00195 GiB <br /> (Serial(SPI))
RAM1 Size
256 MiB268,435,456 B <br />2,097,152 Kib <br />262,144 KiB <br />2,048 Mib <br />0.25 GiB <br />
RAM1 Chip
Samsung K4T1G164QF
nvram Size
ETH chip1
Ethernet Port Count
Wired Standard
IEEE 802.3/3u/3ab

802dot11 OUI: 08:60:6E (1 E, 1 W), 10:BF:48 (3 E, 4 W), 30:85:A9 (3 E, 3 W), 50:46:5D (2 E, 2 W)
Ethernet OUI: 08:60:6E (1 E, 1 W), 10:BF:48 (3 E, 4 W), 30:85:A9 (3 E, 3 W), 50:46:5D (2 E, 2 W)

Stock bootloader
CFE (128k)
Stock FW OS
Expansion IF types
USB 2.0
USB ports
USB Hub Compatible
19 VDC, 1.58 A
Connector type
Serial Port (UART)
AiCloud support

Default SSID: ASUS (99 addl. devices)
, ASUS_5G (46 addl. devices)
Default IP address:
the IP is used by 1293 additional devices
of which 172 are ASUS devices
Default login user: admin
Default login password: admin
admin:admin credentials used by 1316 additional devices
of which 204 are ASUS devices

Askey RT2320W-E61
3rd Party Firmware Support
FCC approval date 30 May 2012
(Est.) release date 10 June 2012
(Est.) initial retail price (in USD): $199.99
UPC 886227214341
(UPC DB, On eBay)
ASIN B008ABOJKS Flag of the United States.svg
Country of manuf China
PWR x 1, LAN x 4, WAN x 1, AIR x 2, USB x 1/Blue
148.8 by 207 by 35.5 millimetres (5.86 in × 8.15 in × 1.40 in)
Radio 1
Broadcom BCM4360
Wireless interface OUI
08:60:6E, 10:BF:48, 30:85:A9, 50:46:5D
Antenna Connector Type
MIMO status
Wireless Standard
IEEE 802.11a/n/ac
up to 1300 Mbps
up to 450 Mbps
up to 54 Mbps
WiFi Operating Frequency
5 GHz
Radio 2
Broadcom BCM4331
Wireless interface OUI
08:60:6E, 10:BF:48, 30:85:A9, 50:46:5D
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
 CPU1 brandRadio1 chip1 brandRadio2 chip1 brand
ASUS RT-AC66U B1 rev A1BroadcomBroadcomBroadcom
ASUS RT-AC66U rev A1BroadcomBroadcomBroadcom
ASUS RT-AC66U rev A2BroadcomBroadcomBroadcom

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

For a list of all currently documented ASUS device with specifications, see ASUS.

1300 Mbps - 3SS 5GHz 802.11ac (80MHz chan.),
450 Mbps - 3SS 2.4GHz 802.11n (40MHz chan.) = AC1750 class


"RT-AC66U" and "REV 1.30" is silkscreened on the (blue) board in the FCC photos.

This router is sold in various brick & mortar stores as the RT-AC66R and RT-AC66W..

The FCC label states the default SSID is ASUS.

See also: ASUS RT-AC66U B1 and Askey
FCC ID: MSQ-RTACHC00 (08/02/2016) (FCC Doc)

On the DD-WRT forums (w/ DD-WRT test build and internal images posted by Magnetron1.1 [hosted on Mediafire], official support added in build 20873 - 20130308 [per the DD-WRT wiki])

50:46:5D OUI on a label shot in the thread
08:60:6E OUI on a DD-WRT build shot in the thread
A later revision A2 model in the thread has "RT-AC66U" and "REV 1.60" silkscreened on the board.

Small info dump in the RT-N66U thread on the DD-WRT forums

Serial log indicates the device has an additional 2MB Serial Flash chip

Reviewed on SmallNetBuilder

10:BF:48 OUI on the label in the internal photos

maylyn's review on the forums

UPC: 886227214341, EAN: 4716<????>4342, OUI: 10:BF:48, revision A1, mfg. year 2012

There is a photo of the RF section in the FCC test report.

The FCC label states the default SSID is ASUS.

Links of Interest

(RT-AC66W)  • (RT-AC66R)


Flashing dd-wrt

  1. Download firmware image here
  2. Set static ip of
  3. reset to defaults in Asus GUI or in recovery mode
  4. In recovery mode, upload BrainSlayer's file
  5. Give the router plenty of time to flash and reboot.
  6. Once able browse to, if you see the change password screen of dd-wrt then do a hard reset which puts the router in recovery mode, select erase nvram and reboot. If you donot see the change password screen start over from step 1.

Flashing Tomato

Source:Guide to Install Tomato firmware on Asus RT-AC66U / RT-N66U / RT-N53 / RT-N16 / RT-N15U / RT-N12 HP B1 C1 D1 / RT-N10P / RT-N10U router (韌體教學)
Note: some people say you need to install DD-WRT first. I do NOT recommend anyone to install DD-WRT first before installing Tomato on Asus routers.

  1. Download a suitable tomato firmware as described above
  2. Install the Asus router utility from the CD that came with the router. Run \Utility\setup.exe from the CD to install it. If you no longer have the CD you can also download it from the Asus website.
  3. Disable Firewall on your computer.
  4. Disable anti-virus on your computer.
  5. Connect your computer to one of the LAN ports of the router with an ethernet cable.
  6. Assign a static IP of and subnet mask to your computer LAN port.
  7. Disconnect the router WAN port if you already have a cable plugged into that port.
  8. From Windows Start menu, run ASUS Utility -> RT-N Wireless Router -> Firmware Restoration.
  9. Click the Browse button and select the file that you downloaded in step #1. Don’t click the upload button yet.
  10. Put the router in recovery mode: Unplug the power cord of the router. Hold down the black Restore button using a pen (not the red button). Plug the power cord back in. Once the power light starts flashing slowing, release the Restore button. The power light should continue to flash. The flashing light means the router is ready to accept the new firmware in recovery mode.
  11. Click the upload button in the Restoration utility. If it warns about incorrect Asus firmware, ignore it. The firmware should now start uploading into the router. Don’t touch anything while the firmware is being uploaded. (Note: these steps worked when I flashed my RT-N16. However, the utility could not find my RT-N12 B1 when I tried to flash the router, although it did work for other people. After failing for more than a dozen times, I tried to perform the upload first before putting the router in recovery mode, then it finally worked. Later I tried a different unit of RT-N12 B1 strangely it could be flashed the first time using the normal procedure. If neither of these procedures work, please see the Addendum in The Wiert Corner, and the tftp method described by Simeon W in the comments section.)
  12. No matter whether the utility says the upload is completed, or it hangs at a certain percent, DO NOT PANIC, and WAIT FOR FIVE MINUTES before you do anything else.
  13. After five minutes, open a browser and go to Login with user “admin” (or “root”) and password “admin”. You should be logged into Tomato.
  14. Administration -> Configuration -> Restore Default Configuration -> Erase all data in NVRAM memory(thorough) -> OK (Note: there is a forum report saying this reset function does not work properly on RT-N53 – in this case, try the hardware reset button.)
  15. After it is completed, login again, enable DHCP (for Toastman Builds), change admin password, enable WiFi security if you use WiFi, plug in your WAN connection and configure it. Also take a look at the CPU frequency, you may need to manually change it if it is not correct. (Note: overclocking your router is usually not a good idea from my experience.)
  16. Change your computer LAN port back to use DHCP (dynamic address) and dynamic DNS.


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!

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, samba, dlna, raid support 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


Asus' Images
Magnetron1.1's Unit


jffs Issue in DD-WRT

This problem is caused by the firmware encountering an unmarked bad block during an erase operation while attempting to setup a JFFS2 filesystem on device /dev/mtd/4.

Most people will probably never experience this problem. The AC66U, the D1800H, and the Buffalo WLI-H4-D1300 Media Bridge use the same Samsung flash memory chip. In my case, 4 of my 5 D1800H's had the problem but my D1300 didn't. Neither of my AC66U's had the problem. One person on one of the AC66U threads reported having the problem; here's a link to his post.

If you have the problem, you will not be able to create or copy directories and files to /jffs. Here are some example error messages:(this list was shortened to save space - it can go on for several pages)

root@WZR-D1800HRT2:~# dmesg|grep jffs
jffs2: jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x05ee0020: 0xe952 instead
jffs2: jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x05ee0024: 0x0e6d instead
jffs2: Further such events for this erase block will not be printed
jffs2: Old JFFS2 bitmask found at 0x05efc7fc
jffs2: You cannot use older JFFS2 filesystems with newer kernels
jffs2: Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes
jffs2: empty_blocks 379, bad_blocks 1, c->nr_blocks 760

Also the Status -> Router webpage will show that JFFS2 has no free space.

To fix this problem try the following at a command line prompt:

flash_erase -j /dev/mtd/4 0 0 && reboot

This command erases and marks bad any bad blocks encountered so that they can be "skipped" and formats the partition to JFFS2 specifications. I believe the firmware uses the mtd erase command which seems to fail at handling bad blocks. The flash_erase command needs to be run only once.

- Magnetron1.1

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:

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


See also