Tomato Firmware on an ASUS RT-AC56U Router

I recently purchased an ASUS RT-AC56U router with the intention of flashing the firmware from the stock ASUS firmware to Tomato by Shibby – I want the OpenVPN client functionality to use with my VPN provider. This router would replace my LinkSys E3000 which could barely connect me to the Internet, let alone VPN.

The whole process seemed simple enough, but of everything I found online, none was 100% complete. So, here you go:

  1. Some say to flash DD-WRT first, others say to go right to Tomato through the default ASUS interface. You do not need to flash DD-WRT first.
  2. Download whichever RT-AC56U-ARM firmware you need; for me, I did not need USB or any of the other fluff, so I avoided the All-In-One (AIO) firmware, and grabbed the latest (v123 at that time) of the VPN version: tomato-RT-AC56U-ARM–123-VPN-64K.trx
  3. Put the router into recovery mode: power-off with the button, holding the reset button, power back on and wait a few seconds. The power LED should start to blink. It’s now in recovery mode.
  4. In recovery mode, the router seems to use default to an IP of 192.168.1.1 – make sure whatever computer you’re using for this process is on that subnet. Open a web browser and open http://192.168.1.1 and you should see a pretty basic webpage. Locate the TRX file and click Upload. Now wait. Give it about 5 minutes.
  5. After about 5 minutes, power off the router using the power switch. Others say that once Tomato is flashed, power-off, hold the WiFi button and power back on. That is incorrect – you have to hold the WPS button until the power LED starts to pulsate, not the WiFi button. Holding the WiFi button will simply put you back in recovery mode and you will continue to repeat the process indefinitely. Hold the WPS button for 10-15 seconds and you will be 100% good to go. Now you can login to Tomato (admin/admin) and wipe the NVRAM.
  6. Login, go to Administration -> Configuartion -> Restore Default Configuration -> Erase All Data in NVRAM (thorough). Sit back and wait for a few minutes and you’re all done!
  7. Enjoy Tomato and OpenVPN (or whatever you want it for).

22 Comments

  1. I just wanted to say thanks.
    I did spend a full afternoon trying with dd-wrt, tomato with the WiFi button back and forth few times until I’ve discover your article. The WPS did the job nicely!

    Appreciated

  2. Glad I stumbled on this guide. Thought I’d have to go back to standard firmware as I could only telnet in after a Tomato install, no GUI available. What was missing from the instructions I’d followed was anything at all to do with holding down any buttons after firmware update. “Hold the WPS button for 10-15 seconds and you will be 100% good to go” did the trick though, GUI appeared after that. Thanks.

  3. Hello,
    thanks for the good review! I have three questions though:

    – How reliable is the Tomato firmware on that router? Any problems?
    – How fast is your internet using VPN? What are your download speeds?
    – How do you update the firmware when a new version is out?

    Thanks in advance for answering my questions.

    • To be honest, within a few days of writing this guide, I dropped Tomato and moved VPN to a Windows VM with Internet Connection Sharing enabled (sharing the OpenVPN connection). Not because of Tomato, but because while running OpenVPN on the ASUS router, I noticed a download speed drop of about 60% and upload was below 50% of normal, while CPU usage on the ASUS was minimal.

      Moving OpenVPN to a Windows Server 2012 R2 VM w/ICS, I get 100% of both upload and download speeds and haven’t looked back. I’ve been meaning to post a guide on doing that, but just haven’t gotten around to it.

      (disclaimer: through my employer, I have MSDN – Visual Studio Enterprise, which gives me access to all Microsoft software, legitimately, for free (well, no cost to me personally). I have a Hyper-V 2012 R2 Datacenter cluster and can spin up new VMs as required)

  4. Hello,

    I flashed my RT-AC56U router with the last version of tomato.
    It seemed to work, I have access to the configuration page of my router but no internet connection.
    On my computer I see my network, my modem is on, I have internet using WiFi directly from my modem so it is working.
    But through the router I have no internet connection, is there a option to check with tomato?

    Regards

      • Yes I did.
        I reboot but nothing. I even installed the AIO firmware to try.
        Nothing seems to work.
        And I can’t put back the stock firmware from asus the restoration mod stuck at 60 or 90%.
        I’m looking for solution but I can’t find a forum and on the tomato site there is nothing.
        Still looking to find help somewhere.

        Thx anyway.

  5. I just did this to my ASUS RT-AC56U but for some reason I had A LOT of trouble getting into recovery / rescue mode. The power LED would blink but I could not access it through the Web UI What finally worked as setting the computer’s IP to a static 192.168.1.10 with a subnet of 255.255.255.0. Boot the router normally and connect to the web UI through 192.168.1.1. Now power off and then reboot into rescue mode. When doing so the second you notice the power LED start to blink release the button. For some reason when I held it a second or too after it was blinking I could not connect. Once released right away try to access the rescue web UI through 192.168.1.1. Do not wait a long time to do this.

    By completing the above I was finally able to flash the tomato firmware without issue. It was the getting to the firmware flash page though that gave me issues.

    One note, after flashing tomato only the power led & rear ethernet led’s will work. The others remain off. Just mentioning in case this was a deal breaker or someone thought they did something wrong.

    • The note about the LED’s is extremely crucial. Unfortunately I was unable to find it on any blog or forum. Stumbled upon this comment by accident. Had to install firmware several times thinking that I did something wrong.

      Thanks Chris.

  6. It works like this guys, but most of you probably already (dont) know this lol, simple, disconnect power to router, press and hold reset with pen while applying power, notice, I did not say use the power button?

    Keep reset button pressed for about 30 seconds after plugging in, then you will see the slowest flashing blue light on earth..

    Load up asus rescue 2000 utility, or use asus miniCFE @192.168.1.1

  7. Thank you. I managed to run Tomato following your instructions, though not without difficulties. In recovery mode I could only open 192.168.1.1 in a private browser windows, and then it wouldn’t let me upload alternative firmware. So I used the Asus firmware restoration tool to flash Tomato which worked.

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