Installing Tomato on ASUS RT-AC3200 Router

I’ve been using  DD-WRT and Tomato firmware on ASUS routers for some years now. Today, I installed the RT-AC3200 and, in the end, it couldn’t have been easier—comparatively speaking. You can find a lot of posts about installing Tomato on ASUS routers because it’s not simple. You can’t simply download an executable and click on it. But this was certainly easier that I’ve ever found it to be.

I pulled the new router out of the box and fired it up in Rescue Mode. I had no interest in the default firmware and did not bother with the factory setup.

Based on a post by Ted Parvu about installing to the RT-68U, the first thing I tried was to use the BroadCom CFE Web Server but it appears to be disabled on the RT-AC3200. So I then tried the ASUS Firmware Restoration utility which is only available for Microsoft Windows. This tool is really finicky but I’ve always been able to make it work, after a fashion. I tried twice but could not make a connection to the router. This problem is common and it usually takes me the better part of an hour to actually make it work but I wanted to try another route.

Chris Hardie wrote of installing to the RT-66U using a TFTP client. The TFTP server in the router appears to be part of the Broadcom CFE, as well. I’ve worked with many routers and switches that use this method for firmware updates so TFTP is well known to me.

After successfully transferring the firmware, I waited five minutes for the router to finish with the file and then rebooted, connected via Telnet, and cleared the Non-Volatile RAM—necessary for installing Tomato. After rebooting again, the router went into a continuous reboot cycle.

This was disappointing but hardly surprising—I’ve been down this road many times with routers. But before restarting from Rescue Mode, again, I remembered another method of clearing the NVRAM from Ted’s post. I rebooted the router while holding the WPS button until the (1) LED on the router started blinking fast and, shortly afterward, was able to access the Web UI.

The problem has always been getting the firmware to the router. Using TFTP, this was so easy I barely noticed. Hopefully, I’ll never have to use the Firmware Restoration utility again.


This is not “Routers for Dummies.” If you aren’t comfortable with installing third-party firmware, or expect the process to go without a hitch, do not touch your router in any way not sanctioned by the manufacturer. You can Brick the device if you’re not careful and the manufacturer will not help you. Installing third-party firmware voids any warranty. If you have not done this before, and are still not scared off, I suggest you read more on the subject before continuing. 

  1. Download the Tomato firmware you wish to install.
    Download a TFTP Client application. You can find free ones anywhere so just search for one.
    Download the latest firmware for the RT-AC3200, and the Firmware Restoration Utility from the ASUS Support Site. You will not be using either of these files but it’s a good idea to have them in case you need to restore the factory firmware.
    It is highly recommended that you scan anything you download from the Internet for viruses.
  2. Disable all network adapters on your computer except for the primary Ethernet adapter.
    This is probably not necessary but I have always found it was required for using the Firmware Restoration utility, which we are not using here, so this is just a precaution.
  3. Configure your primary Ethernet network adapter to the IP address with netmask and connect it to the LAN 1 port on your router.
  4. Start a continuous ping from your computer to the router IP address of
    For Windows, start a continuous ping using the -t option.
  5. Power off the router and wait 30 seconds.
  6. Using the end of a paperclip, pen, or pencil, hold down the recessed reset button on the back of the router and power it up. Keep holding down the button until the power LED starts blinking slowly and then release it.
  7. Wait for the ping to see a response from the router. It will now be in Rescue Mode.
  8. Using your TFTP client, connect to the router IP address of and transfer the firmware file in binary mode (binary is most-likely the default and, in some cases, the only transfer mode available).
    Wait 5 minutes for the router to finish loading the new firmware.
  9. Power off the router.
  10. Press and hold the WPS button on the back of the router and power it up. Keep holding down the button until the power LED begins to blink rapidly and then release it. This could take as long as 30 seconds.
  11. Power-cycle the router if it does not reboot on it’s own.
  12. Wait for the ping to see a response from the router.
  13. Reconfigure your primary Ethernet network adapter to DHCP and reset your network connection.
  14. Access the router Web UI at

This procedure was accomplished in less than 15 minutes. I hope it helps you, too.

About sthames42

A truly brilliant software engineer of great wit and humility. Once young and fit, a great colleague, and serious danger to the ladies. Now old, fat, and married fortunately, but still sharp as a marble.

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