Asus RT-N66U

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[[Image:ASUS RT-N66U.jpg | right | 360px]] [[Image:ASUS RT-N66U.jpg | right | 360px]]
-=Preliminary=+This 'Dark Night' presents significant risk to bricking that requires careful adherence to the installation process. However, there is a built-in and robust Recovery Mode. The NVRAM issue has been resolved in newer CFE versions (and K3X builds).
-This 'Dark Night' is a very powerful piece of equipment and the NVRAM issue has been resolved, however, it presents significant risk (bricking) that requires careful adherence to the installation process.+
-Note on 26-Jan-2013: Until someone updates this page (with CFE update etc.), you may want to read here: http://charleswilkinson.co.uk/2012/12/22/dd-wrt-on-the-asus-rt-n66u-with-64k-cfe/+=Hardware [http://en.techinfodepot.shoutwiki.com/wiki/ASUS_RT-N66U Specifications]=
 +{| border="1" cellspacing="0"
 +!CPU
 +|Broadcom 4706 @ 600MHz
 +|-
 +!Flash/RAM
 +|32MB / 256MB
 +|-
 +!Wireless support
 +|2.4GHz and 5GHz bands
 +|-
 +!Wireless controller
 +|[http://www.broadcom.com/press/release.php?id=s474934 Broadcom BCM4331]
 +|-
 +!MIMO config
 +|3x3 (both bands) (see [https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=86437&start=26 Ref: forum])
 +|-
 +!ETH chip
 +|Broadcom BCM4706
 +|-
 +!Switch
 +|Broadcom BCM53125
 +|-
 +!Ports
 +|Gigabit LAN (4) and WAN (1)
 +|-
 +!USB
 +|2x USB 2.0
 +|-
 +!Other
 +|Micro SDHC socket (internal)
 +|-
 +!Power supply
 +|DC Output, 19 V, max. 1.58 A current (=> max 30W)
 +|-
 +!Serial header
 +|8, n, 1, no flow control, 115200.
 +|}
-====NVRAM issue====+===Reset button for Recovery===
 +Pressing the Reset button (labeled like ' > o < ') at powerup will put the N66U into recovery mode.
 +*Press and hold the reset button then plug in power until the power LED starts blinking. Access recovery mode at 192.168.1.1.
-15-May-2015 The command: [https://www.dd-wrt.com/wiki/index.php/Asus_T-Mobile_Cellspot#Procedure nvram get bl_version] can be issued to determine the CFE version if you have TELNET or SSH access. The Cellspot wiki contains links to many tools and articles to change the CFE. '''Please consider posting a link to a 64K CFE for future users if you have the knowledge \ resource to do so and delete this statement.+===WPS button to Clear NVRAM===
-'''+Pressing the WPS button at powerup will reset (clear NVRAM) to default settings.
 +*Press and hold the WPS button while plugging in the power for about ten seconds. All the LEDs should flash, indicating settings have been reset to default settings.
-25-May-2013: Since BrainSlayer posted some experimental K3.X Images, the NVRAM Issue becomes almost obsolete. Please have a look at the [http://www.dd-wrt.com/wiki/index.php?title=Asus_RT-N66U#Installation_Instructions Installation Instructions] for further instructions.+===NVRAM issue===
 +'''<font color="red">IMPORTANT: DO NOT USE K2.6 builds</font> if using CFE v1.0.1.3 (64K nvram) or NEWER!!!'''<br>
 +At launch, the RT-N66U was limited to 32k nvram. However, CFE (bootloader) version 1.0.1.3 added 64k nvram support around April 2013, but was not compatible with DD-WRT firmware at that time. For details, see these forum links to historical nvram and 64K implemention discussions: [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=86437&postdays=0&postorder=asc&highlight=otrw+light&start=1022 Fractal comments] and [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=163479&start=217 "RT-N66 CFE Thread"]
-9-Apr-2013: It seems more recently manufactured units come pre-loaded with the 64K v1.0.1.3 CFE and so are not compatible with standard DD-WRT builds. Flashing a standard DD-WRT build on these devices will result in a brick. If you don't know which CFE version your unit has when running the stock firmware,anyone wishing to flash DD-WRT on this device is advised to follow this guide: http://charleswilkinson.co.uk/2012/12/22/dd-wrt-on-the-asus-rt-n66u-with-64k-cfe/+This was resolved with DD-WRT K3X builds (kernel 3.x) which extended nvram to 64k, and can be used for any CFE version. It was eventually [https://www.dd-wrt.com/forum/viewtopic.php?p=1112621#1112621 extended to 256k].
-1-Nov-2012: Fractal has indicated that the NVRAM is resolved and that 5Ghz is working. +More historical info: http://charleswilkinson.co.uk/2012/12/22/dd-wrt-on-the-asus-rt-n66u-with-64k-cfe/
-[http://www.dd-wrt.com/phpBB2/viewtopic.php?t=86437&postdays=0&postorder=asc&highlight=otrw+light&start=1022]+
-30-Oct-2012: [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=163479&start=217 RT-N66 CFE Thread] Link to discussion implementing 64K: not sure that this is ready for prime time yet, however, if you try this and feel it is ready, UPDATE THIS STATEMENT and publish the procedure, limitations, and results.+'''For newer CFE version updates''' and procedures see here: [https://www.snbforums.com/threads/cfe-bootloader-update.8259/ SNB Forums]<br>
-=== DD-WRT Alternatives ===+Note: CFE can be thought of, as a bootloader for routers. The CFE is what loads the firmware when using ASUS Recovery Utility (and/or a TFTP tool)
-As of this writing (June 30, 2012) user Merlin has implemented a solution, that lives with 32k NVRAM for CFE, but extends to ~60k NVRAM in firmware.+
-* download: http://www.mediafire.com/asuswrt-merlin/ +
-* source code: https://github.com/RMerl/asuswrt-merlin/+
-* home page: http://www.lostrealm.ca/tower/node/79+
-As of July 16, 2012, TomatoUSB, Shibby http://tomato.groov.pl/download/K26RT-N/build5x-097-EN/Asus%20RT-N66u%2064k/ also has implemented a 64k NVRAM solution that lives with 32K NVRAM for CFE+=====CFE Version (or Update)=====
 +[[Asus_RT-N66U#DD-WRT_Alternatives|AsusWRT-Merlin]] can be installed to enable telnet/ssh. telnet/ssh and then be used to check the CFE version. DD-WRT can then be flashed directly from Asuswrt-Merlin
-=Hardware=+Find the CFE version:
-The ASUS RT-N66U is a Dual Band N-Router (2.4GHz and 5GHz bands) with lots of RAM (256Mb) and FlashRAM (32Mb), so it is well equipped to run DD-WRT +*in telnet/ssh type: nvram get bl_version
 +*or look at the CFE partition. In telnet/ssh type: strings /dev/mtd0ro | grep bl_ver
-The ASUS RT-N66U is in the GigaBit Routing class, meaning it can route at higher speeds than a 100Mbps WAN connection can handle. [[Asus_RT-N66U#Performance|Performance]] details below. 
-If you are looking for less expensive routers, that are also well suited to run DD-WRT, you might want to check out the [[Asus RT-N16]] Single Band N-Router (2.4GHz only) but still with lots of RAM (128Mb) and FlashRAM (32Mb). Even cheaper is the [[Asus RT-N10U]] Single Band N-Router with 32Mb RAM and 8Mb FlashRAM. See also [http://promos.asus.com/US/ASUS_DD-WRT/index.htm ASUS Promo] page+ToDo:
 +* link to Asus CFE sources
 +* determine if updating to latest official Asus Firmware will also update to newest CFE version
 +* newest CFE version (as of July 2020) is 1.0.1.9
 +* how to update the CFE
-==Hardware Specifications==+===K3.X Builds===
-* Dual Band Router - 2.4GHz and 5GHz bands+*Use RT-N66U.trx ''big'' or ''mega'' builds in the ''Broadcom_K3X'' folder. [https://forum.dd-wrt.com/phpBB2/viewtopic.php?p=1150414 Forum note] about the difference between ''mega'' and ''big''
-* Wireless controller [http://www.broadcom.com/press/release.php?id=s474934 Broadcom BCM4331]+*See [[Firmware_FAQ#Where_do_I_download_firmware.3F|Where do I download firmware]] for links and read forum build threads.
-* MIMO 3x3 on both frequencies (see [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=86437&postdays=0&postorder=asc&start=26 Forum, BrainSlayer])+
-* Gigabit LAN and WAN switching+
-* 2x USB 2.0 connectors+
-* CPU [http://www.broadcom.com/products/Wireless-LAN/802.11-Wireless-LAN-Solutions/BCM4706 Broadcom 4706] @ 600MHz+
-* 256MB RAM+
-* 32MB FlashRAM+
-* Built-in Micro SDHC socket +
-* Power supply: DC Output, 19 V, max. 1.58 A current (=> max 30W)+
-==Know your hardware buttons==+Note: do NOT use build 40559 - 40559 is broken for most routers, despite being the recommended build for many routers in the Router Database. Search forum "New build" to get the latest updated info about builds (noted Aug 2020).
-'''Reset button:'''+
-pressing the Reset button while power-up, will put this ASUS router in recovery mode. +
-That is: press and hold the reset button, keep pressing the reset button while plugging in the power, then keep holding the reset button pressed for about ten seconds until the power led is blinking slowly, then release the reset button. The router is now in recovery mode.+===K2.6 Builds===
 +USB (and thus MMC) also does not work in K2.6 builds. USB devices cause a kernel panic: see [http://svn.dd-wrt.com/ticket/2580 SVN ticket]. Use a K3.x build (see above), which also works around the NVRAM issue.
-'''WPS button:'''+Noted Aug 2020: All K2.6 builds after 43136 are likely broken.
-pressing the Red WPS button while power-up, will clear the NVRAM. All settings are stored in NVRAM of this ASUS router. Clearing the NVRAM is the most efficient way to reset the router to default settings.+
-That is: press and hold the WPS button, keep pressing the reset button while plugging in the power, then keep holding the WPS button pressed for about ten seconds, then release the WPS button. All settings have now been wiped, and default settings will be used.+=== DD-WRT Alternatives ===
 +User Merlin implemented a solution in mid-2012 to extend the original 32k NVRAM CFE to ~60k NVRAM in firmware
 +* After 380.70 Asuswrt-Merlin stopped supporting RT-N66U. So earlier versions will still work (to enable SSH/Telnet)
 +** Homepage: https://asuswrt.lostrealm.ca/
 +** Download: https://sourceforge.net/projects/asuswrt-merlin/files/
 +**Source code: https://github.com/RMerl/asuswrt-merlin/
 +* For a Asuswrt-Merlin version that still supports RT-N66U
 +** see: [https://www.snbforums.com/threads/fork-asuswrt-merlin-374-43-lts-releases-v44ea.18914/ snbforums post] where the first entry keeps getting updated with the latest information.
-=Installation Instructions=+TomatoUSB [http://tomato.groov.pl/ Shibby] also implemented a 64k NVRAM solution for 32K NVRAM CFE in 2012.
-====K3.X Builds====+
-'''8-Mar-2015: 26138 is a good (recommended) build for the RT-N66U:+===Historical Build Information===
-* [ftp://ftp.dd-wrt.com/betas/2015/02-04-2015-r26138/broadcom_K3X/dd-wrt.v24-26138_NEWD-2_K3.x-big-RT-N66U.trx Big]+This is only potentially relevant if using builds from 2015 and earlier.
-* [ftp://ftp.dd-wrt.com/betas/2015/02-04-2015-r26138/broadcom_K3X/dd-wrt.v24-26138_NEWD-2_K3.x_mega_RT-N66U.trx Mega]+*If already running a custom 64K Build like Fractal or Kong with CFE 1.0.1.3, [ftp://ftp.dd-wrt.com/betas/2015/02-04-2015-r26138/broadcom_K3X/dd-wrt.v24-26138_NEWD-2_K3.x_mega-nv64k.bin 26138 mega nv64k] must be used to upgrade. Since K2.6 Builds have an embedded check, you need to use those special nvXXk trailed images. On K3.X this check has been removed and you can simply upgrade from a previous K3.X.
 +*With K3.X Broadcom builds, the CFE version is less concerning since DD-WRT detects it automatically to extend the 32KB limitation.
 +*Build 24461 BRICKS the RT-N66U, but recover is possible through the mini CFE web interface.
-'''9-Sep-2014''': new K3.X builds are now also available at [ftp://ftp.dd-wrt.com/betas/ FTP dd-wrt.com/betas] and [http://www.dd-wrt.com/site/support/other-downloads?path=betas%2F WWW dd-wrt.com/betas] 
-:::::Select: year -> release number -> broadcom_K3X -> ......RT-N66U.trx file 
-'''25-May-2013''': Since the experimental [ftp://ftp.dd-wrt.com/others/eko/BrainSlayer-V24-preSP2/2013/05-27-2013-r21676/broadcom_K3X-EXPERIMENTAL/ K3.X Broadcom Builds] are out, you do not need to care what CFE you have. DD-WRT detects it automatically and extends 32KB NVRAM Version to 64KB. Which Image you have to flash, depends on your previous Image ( Stock, Merlin, DD-WRT K2.6 ).+=Installation Instructions=
-* If you have Stock or Merlin firmware: flash [ftp://ftp.dd-wrt.com/betas/2015/02-04-2015-r26138/broadcom_K3X/dd-wrt.v24-26138_NEWD-2_K3.x_mega_RT-N66U.trx 26138 mega].+Read the [[Firmware FAQ]], [https://www.dd-wrt.com/phpBB2/viewtopic.php?t=51486 Peacock Announcement], new build, and model-specific threads.
-* For DD-WRT K2.6: It depends how much NVRAM ( 32KB / 64KB ) you currently have.<br>For 32KB, flash [ftp://ftp.dd-wrt.com/betas/2015/02-04-2015-r26138/broadcom_K3X/dd-wrt.v24-26138_NEWD-2_K3.x_mega_RT-N66U.trx 26138 mega].+
-* If you are already on a custom 64K Build like Fractal or Kong with CFE 1.0.1.3, you need to flash [ftp://ftp.dd-wrt.com/betas/2015/02-04-2015-r26138/broadcom_K3X/dd-wrt.v24-26138_NEWD-2_K3.x_mega-nv64k.bin 26138 mega nv64k]. Since K2.6 Builds have an embedded check, you need to use those special nvXXk trailed images. On K3.X this check has been removed and you can simply upgrade from a previous K3.X to newer svn using dd-wrt.v24-YYYYY_NEWD-2_K3.x_mega.bin.+
-====K2.6 Builds====+===Preparation===
 +* If upgrading to DD-WRT from other firmwares, then use a '''*.trx''' file, as in '''*_RT-N66U.trx''' file for initial flash and upgrades, '''or only half the memory will be available''' (with ASUS routers, using a *.trx file is always a safe bet).
 +* If you are upgrading from one version of DD-WRT to a different (newer/older) version of DD-WRT, you can also use the firmwares that end in '''*.bin'''. as in '''_mega.bin''' or '''_big.bin'''
 +* '''<font color="red">IMPORTANT:</font>''' determine what version of CFE you have on your router,
 +: '''<font color="red">if CFE v1.0.1.3 (64K nvram) or 'NEWER' - DO NOT USE K2.6 builds</font>'''
 +* If using Older CFE (32K nvram) you can use K2.6
 +* Reset '''BEFORE''' and '''AFTER''' firmware upload. If upgrading from DD-WRT to a newer version of DD-WRT, then ''before'' is (mainly) optional.
-USB does not work in K2.6 builds, any attempt to use a USB device will cause a kernel panic see this [http://svn.dd-wrt.com/ticket/2580 trac ticket]. If you want USB functionality with DD-WRT you'll need to use a K3.x build as the problem is fixed in K3.x builds, but won't however be fixed for K2.6 builds.+=====Upload via Web GUI =====
 +#[[Asus_RT-N66U#WPS_button_to_Clear_NVRAM|Reset NVRAM via WPS button]] , or select WebGUI option: Factory Default settings.
 +#Upload the DD-WRT build using the stock web GUI (use file ending in .trx or .bin, according to description under [[Asus_RT-N66U#Preparation|Preparation]]).
 +#Wait until the router reboots itself, which '''can take at least 10 minutes''' (some times 30 minutes or more). Be patient and wait until you get a response from both ping and the routers WebGUI when you use your PC to access the router.
 +#[[Asus_RT-N66U#WPS_button_to_Clear_NVRAM|Reset NVRAM via WPS button]], or select WebGUI option: Factory Default settings. Wait for the router to reboot!!
-'''8-Mar-2015: [http://www.desipro.de/ddwrt-ren/K26/r22000++/kingkong-nv64k-RT-N66U-broadcom.trx Kong 22000++] is a good (recommended) build for the RT-N66U with 64K CFE'''<br>with fix for the serious [http://www.dd-wrt.com/site/content/heartbleed-dd-wrtdd-wrt-online-services Heartbleed vulnerability].+Note: If you are having trouble uploading a newer version of DD-WRT, using the WebGUI, then you might want to try to use a different browser. Sometimes it solves the problem.
-'''9-Apr-2013:''' It seems more recently manufactured units come pre-loaded with the 64K v1.0.1.3 CFE and so are not compatible with standard DD-WRT builds. Flashing a K2.6 DD-WRT build on these devices will result in a brick. As it is impossible to know which CFE version you unit has when running the stock firmware, anyone wishing to flash DD-WRT on this device is advised to follow this guide: http://charleswilkinson.co.uk/2012/12/22/dd-wrt-on-the-asus-rt-n66u-with-64k-cfe/ These instructions should be updated when an official build becomes available.+=====Upload via ASUS Recovery Utility=====
 +#Set your computer to a [[Static_IP|static IP]] (e.g. 192.168.1.12), subnet 255.255.255.0, default gateway 192.168.1.1
 +#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.
 +#Access the Asus CFE recovery mode by issuing 192.168.1.1 in browser field.
 +#Browse to select the DD-WRT trailed build ('''N66U big or mega .trx''') then click ''Upload''.
 +#Wait until the router reboots itself, which '''can take at least 10 minutes'''.
 +#If it doesn't reboot after 30 minutes, power off for 10 seconds, then reset via [[#WPS_button_to_Clear_NVRAM|WPS]]
 +#Reset (via WPS) or reenter recovery mode and select to ''Restore defaults NVRAM values''
 +#*(Optional?) When it completes (should be quick), type this in the browser field then press enter:
 +#*http://192.168.1.1/do.htm?cmd=nvram+commit
 +#Wait until the router reboots itself, then access the DD-WRT GUI at 192.168.1.1 to set a password.
-'''26-Jan-2013:''' Current versions of dd-wrt from the dd-wrt website will quickly run out of nvram (because of 32Kb nvram issue). For a solution where you update CFE to 64Kb NVRAM - AND - use a version of DD-WRT that has N66_64K fix included see: http://charleswilkinson.co.uk/2012/12/22/dd-wrt-on-the-asus-rt-n66u-with-64k-cfe/ AND http://forums.smallnetbuilder.com/showthread.php?t=8259 - (someone please update the general instructions below, when the official dd-wrt is ready for general deployment on the N66U).+=====Switching from Tomato=====
 +#Navigate to the Tomato firmware update page
 +#*''Administration'' -> ''Upgrade''
 +#Upload the firmware you downloaded in step 1
 +#The router will reset several times and change its IP address to the default one (192.168.1.1).
 +#Navigate to http://192.168.1.1/Factory_Defaults.asp
 +#* The login credentials have been reset to the default dd-wrt username/password (root/admin)
 +#Set "Restore Factory Defaults" to yes and click "Apply Settings"
 +#After reboot, set a new user/password
-Otherwise please note: The RT-N66U does REQUIRE the '''K26''' Firmware builds as Broadcom has not released drivers for the non-K26 builds. (Read more here: [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=52043 Recommended Firmwares]).+::Note: Reset to factory defaults after flashing from Tomato to DD-WRT to avoid undesired behavior and instability.
-Note: use build 18946, it fixes the WAN port issue.+=Upgrade to newer DD-WRT=
 +* [https://www.dd-wrt.com/wiki/index.php/Asus_RT-N66U#WPS_button_to_Clear_NVRAM Clear settings (Clear NVRAM)]
 +* Router should revert to default IP (192.168.1.1), so you may have to change your client's IP to the same subnet (e.g. 192.168.1.2).
 +* Use browser to navigate to 192.168.1.1
 +* DD-WRT GUI: ''Administration'' -> ''Firmware upgrade''
 +* [https://www.dd-wrt.com/wiki/index.php/Asus_RT-N66U#WPS_button_to_Clear_NVRAM Clear settings (Clear NVRAM)]
-===Principle steps===+=Revert to original ASUS firmware=
-* Clear settings ([[Hard_reset_or_30/30/30|Clear NVRAM]]) select Factory Default settings+# Download firmware from ASUS web site
 +# Reset to Factory Default Settings or clear NVRAM
 +# Use the DD-WRT web gui: 'Administration -> Firmware upgrade', to upload the ASUS firmware file you downloaded in step 1.
 +# Reset to Factory Default Settings or clear NVRAM
-* 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+=Mods=
-* Clear settings ([[Hard_reset_or_30/30/30|Clear NVRAM]]) select Factory Default settings+===Internal MicroSD card===
 +The N66U has an unused internal MicroSD card slot, but note that USB (and thus MMC) is not supported on K2.6 builds. However, it is working on K3.x builds. See [http://svn.dd-wrt.com/ticket/2580 SVN ticket]
-* "Upgrade" to your final version of DD-WRT (filename ends in .bin) using Web GUI or Recovery Utility+#Open the case
 +#* Unscrew the four screws at the bottom
 +#* Then you want to release the plastic clips that holds the top and bottom parts together.
 +#* Pry the bottom case outward, which has the male clips.
 +#* For future access, it is recommended to either snip off the female "U" clips on the top cover, or round off the square edges on the male part of the clip with a nail file.
 +#Install MicroSD card
 +#Enable USB features to utilize the MicroSD card
 +*In addition to DD-WRT NAS features, the extra storage can be used to install Optware or [[Adding_Software_Packages_using_Entware-3X|Entware-3X (recommended over Optware)]] with K3.x builds: [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=156013 OTRW Take 2]
 +For easier access, see below.
-* Clear settings ([[Hard_reset_or_30/30/30|Clear NVRAM]]) select Factory Default settings+===Case Top Mod===
 +Spacers (~1/4" to 10mm) can be installed to elevate the case top, which allows easier access to the MicroSD card, and also improve cooling. A piece of dark foam and hole punch can be used to retain the top cover LED lighting.
-::Note: is '''IMPORTANT''' to [[Hard_reset_or_30/30/30|clear NVRAM]] (to select Factory Default settings)''' BEFORE''' and '''AFTER''' upload of any new firmware.+===Overclocking===
 +Overclocking works since CFE 1.0.1.3, while underclocking worked prior to that. Overclocking may cause instability, or services (like QoS) to behave unpredictably
 +*Recommended to improve cooling or ventilation when overclocking, like the case top mod
 +*jwh7 has run @663MHz (CFE 1.0.1.9) without issue for 3 years, with an elevated case top
 +*There is one report of QoS degradation at 632Mhz with K3.X big r27360 (06/18/15)
-===Switching from Tomato===+=Notes=
-# Download the latest K3.x mega build+
-# Navigate to the Tomato firmware update page+
-## Administration > Upgrade+
-# Upload the firmware you downloaded in step 1+
-# The router will reset several times and change its IP address to the default one (192.168.1.1).+
-# Navigate to http://192.168.1.1/Factory_Defaults.asp+
-## The login credentials have been reset to the default dd-wrt username/password (root/admin)+
-# Set "Restore Factory Defaults" to yes and click "Apply Settings".+
- +
-::Note: Many settings carried over from Tomato to DD-WRT for me but it's highly advisable to reset to factory defaults or you will risk damage to your router and instability.+
- +
-===Upload Firmware via Web GUI ===+
-* Clear settings ([[Hard_reset_or_30/30/30|Clear NVRAM]]) select Factory Default settings. +
- +
-* Upload the''' [http://dd-wrt.com/dd-wrtv2/downloads/others/eko/V24-K26/svn18946/dd-wrt.v24-18946_NEWD-2_K2.6_mini_RT-N66U.trx .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. You want both ping response and web-gui response to know that the router is fully re-booted.+
- +
-* Clear settings ([[Hard_reset_or_30/30/30|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 192.168.1.12, Subnet 255.255.255.0, Default gateway192.168.1.1 ([[Static_IP|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 192.168.1.1 in browser field. +
- +
-* Flash the initial DD-WRT build (e.g.) [http://dd-wrt.com/dd-wrtv2/downloads/others/eko/V24-K26/svn18946/dd-wrt.v24-18946_NEWD-2_K2.6_mini_RT-N66U.trx Asus-RT-N66U_18946_mini.trx] build and upload. +
- +
-* 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:+
-:* [http://ftp.dd-wrt.com/dd-wrtv2/downloads/others/eko/V24-K26/svn18946/dd-wrt.v24-18946_NEWD-2_K2.6_mega.bin 18946 Mega]+
-:* [http://ftp.dd-wrt.com/dd-wrtv2/downloads/others/eko/V24-K26/svn18946/dd-wrt.v24-18946_NEWD-2_K2.6_big.bin 18946 Big]+
-:* [http://ftp.dd-wrt.com/dd-wrtv2/downloads/others/eko/BrainSlayer-V24-preSP2/2012/06-08-12-r19342/broadcom_K26/dd-wrt.v24-19342_NEWD-2_K2.6_mega.bin 19342 Mega]+
-:* [http://ftp.dd-wrt.com/dd-wrtv2/downloads/others/eko/BrainSlayer-V24-preSP2/2012/06-08-12-r19342/broadcom_K26/dd-wrt.v24-19342_NEWD-2_K2.6_big_RT-N66U.trx 19342 Big]+
- +
-* 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 http://192.168.1.1/do.htm?cmd=nvram+commit. 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 192.168.1.1 and it should be DD-WRT.+
- +
-=Upgrade to newer DD-WRT=+
-* Clear settings (Clear NVRAM)+
-* Use the DD-WRT web GUI : Administration -> Firmware upgrade+
-* Clear settings (Clear NVRAM)+
-* svn24461 BRICKS RT-N66U. Recover possible through mini CFE webinterface.+
- +
-=Revert to original ASUS firmware=+
-* Download firmware from ASUS web site+
-* Reset to Factory Default Settings or clear NVRAM+
-* Use the DD-WRT web gui: Administration -> Firmware upgrade+
-* Reset to Factory Default Settings or clear NVRAM+
- +
-= Install an internal MicroSD card=+
-'''11 Apr 2014 - Important note:'''+
-USB (and therefor MMC) support does not work on K2.6 builds - it causes a kernel panic. However it is working on K3.x builds. See [http://svn.dd-wrt.com/ticket/2580 SVN Ticket 2580] for more info.+
-== Open the case ==+
-* Unscrew the four screws at the bottom+
-* Then you want to release the plastic clips that holds the top and bottom parts together.+
-* You want to "pry" the bottom case outward. The clips have the male part moulded into the bottom, the female part is moulded into the top cover.+
-* For easier access next time, you can either snip off the "U" clips on the top cover, or round off the square edges on the male part of the clip with a nail file. Either solution makes it easier to get the case apart next time.+
-== Install MicroSD card ==+
-== Make use of the MicroSD card==+
-In addition to the NAS features of DD-WRT, you can use the extra space to install Optware.+
- +
-'''11 Apr 2014:''' Please note that since USB & MMC support is not working on K2.6 builds, you cannot install Optware on K2.6 builds. USB & MCC are working on K3.x builds, however Optware support for K3.x builds is currently considered beta. Having said that, forum member kabadisha has successfully tested installation of Optware on K.3x build 23598 mega on this device using the following instructions: [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=156013 OTRW Take 2]+
- +
-=Performance=+
-This router is in the GigaBit Routing class, meaning it can route at quite a bit higher speeds than a 100mpbs internet connection can handle.+
 +===Performance===
<pre> <pre>
-Test Description RT-N66U+Test Description RT-N66U
-WAN - LAN 732 Mbps+WAN - LAN 732 Mbps
LAN - WAN 729 Mbps LAN - WAN 729 Mbps
-Total Simultaneous 810 Mbps+Total Simultaneous 810 Mbps
Maximum Simultaneous Connections 34,925 Maximum Simultaneous Connections 34,925
Firmware Version 3.1.0.3.90 (stock firmware number) Firmware Version 3.1.0.3.90 (stock firmware number)
-</pre> Sources: [http://www.smallnetbuilder.com/wireless/wireless-reviews/31687-asus-rt-n66u-dark-knight-dual-band-wireless-n900-gigabit-router-reviewed?start=2] Testing methods: [http://www.smallnetbuilder.com/lanwan/lanwan-howto/31103-how-we-test-hardware-routers-revision-3]+</pre>
 +[http://www.smallnetbuilder.com/wireless/wireless-reviews/31687-asus-rt-n66u-dark-knight-dual-band-wireless-n900-gigabit-router-reviewed?start=2 Sources] and [http://www.smallnetbuilder.com/lanwan/lanwan-howto/31103-how-we-test-hardware-routers-revision-3 testing methods]
-=====Overclocking=====+===LAN/WAN issue===
-Overclocking is availible, but does not work yet. CFE Bootloader is using old hndmips.c source and it does not support frequencies higher 600 MHZ. Underclocking is working so far.+There should be no ''vlan0ports'' in nvram for the N66U switch: [https://www.dd-wrt.com/phpBB2/viewtopic.php?p=986347#986347] and [https://www.dd-wrt.com/phpBB2/viewtopic.php?p=936405#936405]<br>
-'''12-Dec-2015''' Note that overclocking to 632Mhz may cause QoS to behave unpredictably. Overclocking may adversely affect other services, YMMV. (QoS degradation observed with K3.0-r27360 (06/18/15) big)+===Links===
- +
-=Links and Notes =+
Primary forum threads Primary forum threads
-* [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=86437&start=1155 Forum: RT-N66U General Discussion]+* [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=171783 One User's Guide] - A users guide for flashing RT-N66U
-* [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=163479&start=451 Forum: RT-N66 CFE Thread] – Information specifically about upgrading to the 64k CFE.+* Possible ways to update CFE (once a 32k+ CFE is released for this router), see [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=86437&postdays=0&postorder=asc&start=496 LOM post]
-* [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=171783 One User's Guide] - A users guide for flashing Rt-N66u+*[[Linking_Routers| Linking Routers]] to cover a bigger area with WiFi
 +*Wireless tweaking: [[Basic_Wireless_Settings|Basic Wireless Settings]] and [[Advanced_wireless_settings|Advanced Wireless Settings]]
 +*External antennas: [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=43810 The CATFISH thread]
 +* A good 2020 [https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=325439 forum thread]
Additional forum threads Additional forum threads
Line 202: Line 215:
* [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=153609&postdays=0&postorder=asc&start=5 Forum: Reason for starting from Build 18946] * [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=153609&postdays=0&postorder=asc&start=5 Forum: Reason for starting from Build 18946]
* [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=154818 Forum: N66U and 32k/64k NVRAM issue] * [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=154818 Forum: N66U and 32k/64k NVRAM issue]
-* [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=155642 Forum: open case, add MicroSD card]. A 32Gb SD card tested, see [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=155642&start=8 Forum]+* [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=155642 Forum: Open case to add MicroSD card], and a 32Gb card tested [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=155642&start=8 here]
* [http://www.techinfodepot.info/index.php/Asus_RT-N66U_B1 techinfodepot.info on RT-N66U] * [http://www.techinfodepot.info/index.php/Asus_RT-N66U_B1 techinfodepot.info on RT-N66U]
* [http://www.smallnetbuilder.com/wireless/wireless-reviews/31687-asus-rt-n66u-dark-knight-dual-band-wireless-n900-gigabit-router-reviewed SmallNetBuilder Review] * [http://www.smallnetbuilder.com/wireless/wireless-reviews/31687-asus-rt-n66u-dark-knight-dual-band-wireless-n900-gigabit-router-reviewed SmallNetBuilder Review]
* [http://service.asus.com/demoui/RT-N66U/EN/index.html Asus Stock UI demo] * [http://service.asus.com/demoui/RT-N66U/EN/index.html Asus Stock UI demo]
- 
-* WAN issue fixed in svn18835, see [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=86437&postdays=0&postorder=asc&start=214 Forum post, Eko] 
-* Serial inside is: 8, n, 1, no flow control, 115200.  
-* Possible ways to update CFE (once a 32k+ CFE is released for this router), see [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=86437&postdays=0&postorder=asc&start=496 Forum, LOM] 
-* Positive report of running svn18740, see [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=86437&postdays=0&postorder=asc&start=706 Forum post] 
- 
-==Generally good to know == 
-* [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=51486 Peacock Thread-FAQ: EVERYTHING you NEED to know! Really!!] All the basics about DD-WRT on Broadcom based routers - A MUST READ Thread!!! 
-* Get the most speed out of your [[Wireless-N_Configuration|wireless-N technology]] 
-* [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=43810 The CATFISH thread - external antenna choice and use] If you need a better WiFi connection - get a more focused antenna!!! 
-* [[Linking_Routers]] to cover a bigger area with WiFi  
[[Category:Asus guides]] [[Category:Asus guides]]

Revision as of 09:16, 8 August 2020

This 'Dark Night' presents significant risk to bricking that requires careful adherence to the installation process. However, there is a built-in and robust Recovery Mode. The NVRAM issue has been resolved in newer CFE versions (and K3X builds).

Contents

Hardware Specifications

CPU Broadcom 4706 @ 600MHz
Flash/RAM 32MB / 256MB
Wireless support 2.4GHz and 5GHz bands
Wireless controller Broadcom BCM4331
MIMO config 3x3 (both bands) (see Ref: forum)
ETH chip Broadcom BCM4706
Switch Broadcom BCM53125
Ports Gigabit LAN (4) and WAN (1)
USB 2x USB 2.0
Other Micro SDHC socket (internal)
Power supply DC Output, 19 V, max. 1.58 A current (=> max 30W)
Serial header 8, n, 1, no flow control, 115200.

Reset button for Recovery

Pressing the Reset button (labeled like ' > o < ') at powerup will put the N66U into recovery mode.

  • Press and hold the reset button then plug in power until the power LED starts blinking. Access recovery mode at 192.168.1.1.

WPS button to Clear NVRAM

Pressing the WPS button at powerup will reset (clear NVRAM) to default settings.

  • Press and hold the WPS button while plugging in the power for about ten seconds. All the LEDs should flash, indicating settings have been reset to default settings.

NVRAM issue

IMPORTANT: DO NOT USE K2.6 builds if using CFE v1.0.1.3 (64K nvram) or NEWER!!!
At launch, the RT-N66U was limited to 32k nvram. However, CFE (bootloader) version 1.0.1.3 added 64k nvram support around April 2013, but was not compatible with DD-WRT firmware at that time. For details, see these forum links to historical nvram and 64K implemention discussions: Fractal comments and "RT-N66 CFE Thread"

This was resolved with DD-WRT K3X builds (kernel 3.x) which extended nvram to 64k, and can be used for any CFE version. It was eventually extended to 256k.

More historical info: http://charleswilkinson.co.uk/2012/12/22/dd-wrt-on-the-asus-rt-n66u-with-64k-cfe/

For newer CFE version updates and procedures see here: SNB Forums

Note: CFE can be thought of, as a bootloader for routers. The CFE is what loads the firmware when using ASUS Recovery Utility (and/or a TFTP tool)

CFE Version (or Update)

AsusWRT-Merlin can be installed to enable telnet/ssh. telnet/ssh and then be used to check the CFE version. DD-WRT can then be flashed directly from Asuswrt-Merlin

Find the CFE version:

  • in telnet/ssh type: nvram get bl_version
  • or look at the CFE partition. In telnet/ssh type: strings /dev/mtd0ro | grep bl_ver


ToDo:

  • link to Asus CFE sources
  • determine if updating to latest official Asus Firmware will also update to newest CFE version
  • newest CFE version (as of July 2020) is 1.0.1.9
  • how to update the CFE

K3.X Builds

Note: do NOT use build 40559 - 40559 is broken for most routers, despite being the recommended build for many routers in the Router Database. Search forum "New build" to get the latest updated info about builds (noted Aug 2020).

K2.6 Builds

USB (and thus MMC) also does not work in K2.6 builds. USB devices cause a kernel panic: see SVN ticket. Use a K3.x build (see above), which also works around the NVRAM issue.

Noted Aug 2020: All K2.6 builds after 43136 are likely broken.

DD-WRT Alternatives

User Merlin implemented a solution in mid-2012 to extend the original 32k NVRAM CFE to ~60k NVRAM in firmware

TomatoUSB Shibby also implemented a 64k NVRAM solution for 32K NVRAM CFE in 2012.

Historical Build Information

This is only potentially relevant if using builds from 2015 and earlier.

  • If already running a custom 64K Build like Fractal or Kong with CFE 1.0.1.3, 26138 mega nv64k must be used to upgrade. Since K2.6 Builds have an embedded check, you need to use those special nvXXk trailed images. On K3.X this check has been removed and you can simply upgrade from a previous K3.X.
  • With K3.X Broadcom builds, the CFE version is less concerning since DD-WRT detects it automatically to extend the 32KB limitation.
  • Build 24461 BRICKS the RT-N66U, but recover is possible through the mini CFE web interface.


Installation Instructions

Read the Firmware FAQ, Peacock Announcement, new build, and model-specific threads.

Preparation

  • If upgrading to DD-WRT from other firmwares, then use a *.trx file, as in *_RT-N66U.trx file for initial flash and upgrades, or only half the memory will be available (with ASUS routers, using a *.trx file is always a safe bet).
  • If you are upgrading from one version of DD-WRT to a different (newer/older) version of DD-WRT, you can also use the firmwares that end in *.bin. as in _mega.bin or _big.bin
  • IMPORTANT: determine what version of CFE you have on your router,
if CFE v1.0.1.3 (64K nvram) or 'NEWER' - DO NOT USE K2.6 builds
  • If using Older CFE (32K nvram) you can use K2.6
  • Reset BEFORE and AFTER firmware upload. If upgrading from DD-WRT to a newer version of DD-WRT, then before is (mainly) optional.
Upload via Web GUI
  1. Reset NVRAM via WPS button , or select WebGUI option: Factory Default settings.
  2. Upload the DD-WRT build using the stock web GUI (use file ending in .trx or .bin, according to description under Preparation).
  3. Wait until the router reboots itself, which can take at least 10 minutes (some times 30 minutes or more). Be patient and wait until you get a response from both ping and the routers WebGUI when you use your PC to access the router.
  4. Reset NVRAM via WPS button, or select WebGUI option: Factory Default settings. Wait for the router to reboot!!

Note: If you are having trouble uploading a newer version of DD-WRT, using the WebGUI, then you might want to try to use a different browser. Sometimes it solves the problem.

Upload via ASUS Recovery Utility
  1. Set your computer to a static IP (e.g. 192.168.1.12), subnet 255.255.255.0, default gateway 192.168.1.1
  2. 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.
  3. Access the Asus CFE recovery mode by issuing 192.168.1.1 in browser field.
  4. Browse to select the DD-WRT trailed build (N66U big or mega .trx) then click Upload.
  5. Wait until the router reboots itself, which can take at least 10 minutes.
  6. If it doesn't reboot after 30 minutes, power off for 10 seconds, then reset via WPS
  7. Reset (via WPS) or reenter recovery mode and select to Restore defaults NVRAM values
  8. Wait until the router reboots itself, then access the DD-WRT GUI at 192.168.1.1 to set a password.
Switching from Tomato
  1. Navigate to the Tomato firmware update page
    • Administration -> Upgrade
  2. Upload the firmware you downloaded in step 1
  3. The router will reset several times and change its IP address to the default one (192.168.1.1).
  4. Navigate to http://192.168.1.1/Factory_Defaults.asp
    • The login credentials have been reset to the default dd-wrt username/password (root/admin)
  5. Set "Restore Factory Defaults" to yes and click "Apply Settings"
  6. After reboot, set a new user/password
Note: Reset to factory defaults after flashing from Tomato to DD-WRT to avoid undesired behavior and instability.

Upgrade to newer DD-WRT

Revert to original ASUS firmware

  1. Download firmware from ASUS web site
  2. Reset to Factory Default Settings or clear NVRAM
  3. Use the DD-WRT web gui: 'Administration -> Firmware upgrade', to upload the ASUS firmware file you downloaded in step 1.
  4. Reset to Factory Default Settings or clear NVRAM

Mods

Internal MicroSD card

The N66U has an unused internal MicroSD card slot, but note that USB (and thus MMC) is not supported on K2.6 builds. However, it is working on K3.x builds. See SVN ticket

  1. Open the case
    • Unscrew the four screws at the bottom
    • Then you want to release the plastic clips that holds the top and bottom parts together.
    • Pry the bottom case outward, which has the male clips.
    • For future access, it is recommended to either snip off the female "U" clips on the top cover, or round off the square edges on the male part of the clip with a nail file.
  2. Install MicroSD card
  3. Enable USB features to utilize the MicroSD card

For easier access, see below.

Case Top Mod

Spacers (~1/4" to 10mm) can be installed to elevate the case top, which allows easier access to the MicroSD card, and also improve cooling. A piece of dark foam and hole punch can be used to retain the top cover LED lighting.

Overclocking

Overclocking works since CFE 1.0.1.3, while underclocking worked prior to that. Overclocking may cause instability, or services (like QoS) to behave unpredictably

  • Recommended to improve cooling or ventilation when overclocking, like the case top mod
  • jwh7 has run @663MHz (CFE 1.0.1.9) without issue for 3 years, with an elevated case top
  • There is one report of QoS degradation at 632Mhz with K3.X big r27360 (06/18/15)

Notes

Performance

Test Description                                 RT-N66U
WAN - LAN	                                 732 Mbps
LAN - WAN                                         729 Mbps
Total Simultaneous                              810 Mbps
Maximum Simultaneous Connections   34,925
Firmware Version                                3.1.0.3.90  (stock firmware number)

Sources and testing methods

LAN/WAN issue

There should be no vlan0ports in nvram for the N66U switch: [1] and [2]

Links

Primary forum threads

Additional forum threads