Netgear WNDR3400

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[edit] Important Notes

Only version 1 is supported. Versions 2 & 3 are not yet officially supported.

There is an unofficial port of dd-wrt to the version 2 hardware it is discussed here [1] It is located on myopenrouter here [2]

There is an unofficial port of dd-wrt to the version 3 hardware it is discussed in this thread here [3]

Use only K2.6 builds with nv64k in the name, K3 builds are often too big but you can check if they will fit! They must be less than 7995392 bytes in size. Always start with a K26 mini build though.

Read Peacock topic (at top of Broadcom Forum). Read it all. Carefully.

DD-WRT Forums, Report Bugs!

[edit] Hardware Specs

CPU Broadcom BCM4718A1
CPU Speed 480 MHz
Flash ROM 8 MB
Radios 2.4 GHz and 5 GHz
WLAN Support A/B/G/N
WLAN Max Speed 300 Mbps on 2.4Ghz and 300 Mbps on 5Ghz
Antenna Location Internal
Switch 4x 100 LAN + 1x 100 WAN
USB 1x USB 2.0

[edit] DD-WRT Installation

  1. There are two versions of this router with corresponding initial flash mini firmware: K2.6_mini-WNDR3400.chk is for Netgear branded routers and K2.6_mini-WNDR3400_CVNA.chk is for Cablevision routers. See Where do I download firmware? for links. Check the build threads on the forums such as this one for 33772, do not consider this a build recommendation.
  2. Do a factory reset (recessed button on the back), and upgrade with the appropriate mini firmware above. If it complains about downgrading, just Allow.
  3. To gain functionality of the usb port, upgrade to a big nv64 version or a mega nv64 version after flashing the mini version above. Broadcom K3X builds can also be flashed to this router just make sure each build has the routers name in it like step 1 and is less than 7995392 bytes (7808 bytes) in size or you will brick the router. NOTE: this may NOT be the correct size. Firmware revision 46949 Mega bricks this router and it is 7967744 in size
  4. 30-30-30 reset router (as described in Peacock).

[edit] Build Notes

Check every build to make sure that it is less than 7995392 bytes in size or you will brick your router. It is best to check the build threads on the forum. Such as this one for build 33772.

I have tested build 33555 mini (10/20/17) on this router and it flashes and runs fine. This is the second build that patches the KRACK vulnerability in WPA2 and it can be obtained here [4]

  • Version dd-wrt.v24-33772_NEWD-2_K2.6_mega-nv64k.bin bricks this router.
  • Version dd-wrt.v24-33772_NEWD-2_K3.x_mega-nv64k.bin bricks this router.
  • Version dd-wrt.v24-30534_NEWD-2_K2.6_mega-nv64k.bin bricks this router.
  • Version dd-wrt.v24-28493_NEWD-2_K3.x_mega-nv64k.bin bricks this router.
  • Version dd-wrt.v24-33772_NEWD-2_K2.6_mini.bin does not brick this router.
  • Version dd-wrt.v24-46239_NEWD-2_K2.6_big-nv64k.bin runs on this router - tmittelstaedt, tested 5/19/2021
  • Version dd-wrt.v24-48322_NEWD-2_K2.6_big-nv64k.bin runs on this router and appears to be one of the last BIG ones that will fit - tmittelstaedt, tested 2/11/2022
  • Version dd-wrt.v24-50963_NEWD-2_K2.6_mini-nv64k.bin runs on this router - tmittelstaedt, tested 12/06/2022
  • Version dd-wrt.v24-50927_NEWD-2_K2.6_big-nv64k.bin bricks this router - tmittelstaedt, tested 11/21/2022
  • Version dd-wrt.v24-50963_NEWD-2_K3.x_mega-nv64k.bin bricks this router so badly a pin short recovery destroyed it - even though this firmware is smaller in size than 46239 big - tmittelstaedt, tested 12/7/2022
  • Version 46949 Mega and Big brick this router.


[edit] Unbricking

This router can be "bricked" (rendered inoperable) by flashing the wrong firmware; by not following the correct flashing procedure (in Peacock); or by flashing a bad build like 21676 Big.

[edit] Factory method

See Reinstall the firmware on a router without the setup CD recovery tool

[edit] Recovery mode method

This method, which works on the WNDR3800, may also work on the WNDR3400v1.

I tried the recovery method listed for WNDR3800 and couldn't seem to get it to work, it could be the timing. I was trying with linux TFTP and it does try around ten times and started it before and just after starting it but still didn't work.

What does work is a serial recovery, with serial adapter attached here is what worked.

  • Hit CTRL-C then start router
  • Type TFTPD at CFE prompt to start TFTP server
    • Could not get firmware to flash from CFE prompt
  • TFTP either the official netgear firmware or DD-WRT initial flash firmware.
    • Had to use firmware with ".chk" extension, DD-WRT firmware with ".bin" extensions would flash, however, it would stop there and router will not program.
  • Afterwards you can then upgrade to mega or Kong builds.

Gostmn26 15:16, 23 November 2014 (CET)

[edit] Pin short method

If you have bricked your router, and you are willing to accept the risk of damaging it beyond repair (as warned in Peacock), the router can often be recovered by shorting pins as described here.

  • Timing of the pin shorting is tricky -- power on, wait for the lights to flash, then try shorting a few times until the power light starts flashing steadily.
  • Next use tftp2 (with no password) to flash factory firmware.
  • After the flash, wait at least five minutes after the router boots up and the power light becomes steady green before resetting the router.

Here is another overview of the process for the WNDR3400

[edit] Revert to Factory Firmware

  1. Download official Netgear firmware
  2. Reset DD-WRT (recessed button in the back)
  3. Enable telnet under services
  4. Telnet to router (
  5. Issue the command "mtd erase linux" & wait ~3 mins
  6. tftp the official firmware to the router
    • tftp for windows [5] enter router ip, leave password blank, select official firmware file
  7. 30-30-30 reset router (as described in Peacock)