Linksys WRT400N – DD-WRT Installation

Step by step guide on how to upgrade WRT400N from original Linksys firmware to DD-WRT.
This guide is for DD-WRT v24-sp2 released by BrainSlayer on 17.Feb.2011.
In terms of functionality, these steps will basically turn your $80 router into $500 router.

You can watch my video:

Or follow this text guide:

First, do a Hard reset or 30/30/30 of your WRT400N router.

With the unit powered on, press and hold the reset button on back of unit for 30 seconds
Without releasing the reset button, unplug the unit and hold reset for another 30 seconds
Plug the unit back in STILL holding the reset button a final 30 seconds

Now when above reset is done, set a static IP on your computer to Subnet mask should be
In WIN XP this is under networking…
In Windows 7, it’s a bid of pain to get to your lan connection settings, so to immediately open the connection list, you can just type ncpa.cpl into the Start menu search box or into Windows Explorer address bar to get to it.

Anyways, once your pc ip address is changed, open Windows Explorer and navigate to:
or use your fav. ftp client. Copy both files found in this directory to your desktop.

Connect the LAN cable from your computer to a LAN port of your router.
Make sure your router is plugged in.
Nothing should be connected to your computer or the router except the lan cable between them.
Turn your firewall and any wireless computer connections OFF.

Power cycle the router (uplug the power from the router for 30 seconds and then plug it back in)

Open your browser, go to, this will open the linksys webgui and NOT a page that says Management Mode.
If you see management mode, power cycle the router again.

Leave the username blank and enter “admin” as the password, this will let you access WRT400N web gui.
Now, go to Administration and select Firmware Upgrade tab.
Press “Choose file” and then navigate to a desktop folder and select linksys-to-ddwrt-firmware.bin file. Hit upgrade

If your router successfully upgraded, you’ll need to wait FIVE FULL minutes (this is important).

If you don’t get success, repeat steps above. If you still don’t get success, clear your browser cache or try using a different browser to navigate to

Anyhow, now you should be able to access the dd-wrt webgui using a browser at

Now we need to power cycle WRT400N router again.

Try accessing the dd-wrt webgui using by pointing browser at
If it works, do another Hard reset or 30/30/30 on the router.

Open browser again and go to:, then go to Administration and select Firmware Upgrade tab.
Navigate to the desktop folder and select wrt400n-firmware.bin. Hit upgrade!

Wait, it’ll take some time to upgrade. When you get a successful upgrade, wait FIVE FULL minutes.

Reset your computer ethernet connection to auto IP and auto DNS.

At this point you should change the router’s login name and password and Voila, you’ve successfully switched from original Linksys firmware to DD-WRT firmware.
Now you can enjoy whatever DD-WRT feature you were after or choose a different build to upgrade with, really depending on what your needs are.

Watch for future releases at:

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