How To Flash Tomato on the ASUS RT-N66U

The stock firmware on the ASUS RT-N66U might not be too bad, but why settle for it when you can use Tomato instead? Follow these easy steps to install Tomato.

Ever since I started to host this site on vbox, I’ve gone to ridiculous lengths to make sure the server is up and online as much as possible: The server, the internet modem and a router is connected to an APC UPS and I’ve registered the server as a Ripe Atlas node to measure uptime. This weekend I also got a spare router, just in case the one I’m currently using goes tits-up. If it does, it’s not the availability of vbox that concerns me, though: I wouldn’t have wireless internet in the apartment. What would happen then, maybe I would have to read a printed newspaper, like a caveman?

So I bought another ASUS RT-N66U router, just to be on the safe side. It’s a proper workhorse and a great piece of hardware, but it has a bit to be desired on the firmware front. Thankfully, there are some very clever people out there. People so clever, they’re making custom firmware for routers. One of these custom firmwares is Tomato (Wikipedia). The base build hasn’t been updated in the last couple of years, but some of the Tomato modifications are very active. One of these modifications is Shibby‘s, and that’s the version we’ll be flashing.

Warning: Flashing third party firmware will void your warranty. I will not be held responsible if anything goes wrong. Flashing a device’s firmware is always a risky operation, especially when you’re dealing with custom, unofficial firmware. By following this amateurish guide you understand that you might end up with a brick – a useless piece of hardware.
Another warning: Flashing a router with third party firmware isn’t a trivial thing to do, even with the help of this step-by-step guide. Make sure you read through the entire guide at least once before you start so you get an overview of the steps.

With that out of the way, let’s get started (if you are running into any problems along the way, I strongly recommend that you read the comments to this post, as other people might have had the same problem and found a solution).

  1. Download and install the ASUS RT-N66U Firmware Restoration utility from ASUS’ support site. Just enter RT-N66U in the search box and you should be able to find it.
  2. Download the latest version of Shibby’s RT-N66U firmware. Go for one of the ASUS RT-N66u 64K versions. Any of them will work great, take the one with features that best suit your needs. If you’re not sure what your needs are, download the AIO version. There are two language versions on Shibby’s site, one Polish and one English; The Polish version is in the directory ending with -PL, the English version in the directory ending with -EN. So make sure you’re downloading the correct one.
  3. Connect the RT-N66U to your network with a network cable, but don’t turn it on yet. If you have more ASUS routers connected to your network, make sure you isolate the one you will be flashing, or you run the risk of flashing the wrong router (or at least that’s my theory). Isolating the router can be easily achieved by connecting it directly to your computer with a network cable (make sure you connect the network cable to one of the LAN ports on the router, and not the WAN port) and disconnecting your computer from any wireless network you might be connected to.  At this point you don’t need an internet connection (since you have all the files you need now and you see this guide).
  4. Open the ASUS Firmware Restoration utility and load Shibby’s RT-N66U firmare, but don’t start the restoration process just yet.
  5. If the RT-N66U is on, turn it off.
  6. While holding the reset button, turn the router on. After a short while, the power LED should start blinking. Release the reset button. The router is now in emergency firmware restore mode, ready to be flashed.
  7. Start the restoration process in the ASUS Firmware Restoration utility.
  8. The utility should upload the firmware to the router and start the restoration process. If you get any warnings that the firmware is unknown, unofficial or similar warnings, just click OK (or similar) and continue. The flashing process might take several minutes. In my case it took more than 5 minutes. Note: Some users have reported that they get an error message (screenshot) from the firmware restoration utility. It seems like the reason for the error is that the flashing process is so slow the restoration utility gives up. But the flashing process is still running on the router. The solution is to just wait, but it’s not clear how long you have to wait. One user reported about 15 minutes, another about 30 minutes, so your mileage will vary. After a while, the router will restart itself, and when it’s done restarting itself, the Wi-Fi light will be turned on. It’s then time to move to the next step.
  9. When the router restarts as described above or the ASUS Firmware Restoration utility reports that everything went OK, you might not yet be able to connect to the router. But there’s no need to panic, you simply have to clear the NVRAM.
  10. Turn off the RT-N66U.
  11. While holding the WPS button, turn the router on.
  12. Keep holding the WPS button for at least 30 seconds and then release it.
  13. The router should now reboot.
  14. After the router has rebooted, open the browser of your choice and go to When prompted to log in, the default user name is root and the default password is admin. You should change the default password after logging in the first time.

Congratulations, you now have one of the finest custom router firmwares available installed on your ASUS RT-N66U.

This guide is based on How to flash RT-N66U with Shibby’s TomatoUSB firmware and ASUS RT-N66U – TomatoUSB firmware Flashing Guide

By Vegard Skjefstad

60 replies on “How To Flash Tomato on the ASUS RT-N66U”

Hey – I don’t get step 5.
You say ‘turn the router on’ … at this point shouldn’t it already be on?
Do you mean off then on?
Also, when do you release the reset button?

Similarly step #11, do you mean press and hold WPS and simultaneously turn on the router?

Hi Jack. I’ve made some subtle changes to the checklist that might help, but here are the answers to your questions:

Step 5 (now step 6): The router should not be turned on at this point (I’ve added a new step to clarify this). It should be turned on while you hold the reset button. The reset button should be released when the power LED is flashing.
Step 11 (now step 12): Yes, press and hold the WPS button and simultaneously turn on the router.

Hi Vegard.

I can’t get to step 7.
The Firmware Restoration app is searching for an available IP address for ever.

Please help.

Are you connected through the router through Wi-Fi or a network cable? I’ve only done the firmware upgrade using a network cable from my computer connected to one of the four LAN ports on the router (make sure you are not connected to the WAN port).

Er.. not ensure that the light is blinking, it wants me to check to see if it is to denote if it’s in recovery mode.

Some more information, the routers power LED is *not* blinking. The only active light is the one indicating my LAN port is in use.

For whatever reason the moderators deleted my post with my issue including some screenshots of what is happening :\

So, I guess to reiterate:

Once the flashing finishes (the firmware is uploaded and it hits 100% on the recovery process), the utility errors out and says that it failed to connect to my device and to check to see if the power light is blinking (it’s not) to denote if it’s still in recover mode.

The comments with the screenshots were stuck in the moderator queue, looks like WordPress does this automatically for comments with links in them.

Anyway, are you sure the router was in emergency firmware restore mode (LED light was blinking) when you started the restoration process from the ASUS utility on your computer?

I have this same issue. Device has already gone through steps up to 9 above. It is right after it hits 100% restored. The recovery app then gives the error mentioned.

I have done some digging but can’t test till tonight but there is talk on the dd-wrt pages that you need to set a static IP (and actually Sabai Tech who use a Tomato derivative also state to set a static IP).

Steps from Sabai Tech:
1) Unplug all network cables from the router and turn the router off. While the router is powered off, hold the reset button and, at the same time, turn the power on to the router. (This will take the router into a special mode).
2) You will need to then set a Static IP address like on your computer with a subnet of (gateway, etc does not matter), and connect that PCs network cable to the router.
3) …Install Firmware
4) Wait 10 minutes then enable DHCP address on your computer.

This is weird, to be honest. I didn’t encounter this error myself. After the recovery utility throws the error, did you try to reset NVRAM (steps 10 and beyond)? It might be that the recovery app tries to re-connect to the router to confirm that everything is A-OK, but it’s not able to because the NVRAM isn’t reset yet.

If you could give this a try and let me know if it works or not, that would be great!

So, I did a full out reset (NVRAM, 30-30-30 reset ,etc) flashed it following your main instructions, got the same error, gave up and left for 2 hours. When I got back the rest of the router’s lights kicked on and it was magically working for no apparent reason what so ever.

Soooo I guess I am good?

The steps provided by Sabai Tech provided no difference, I still had to wait a good hour or so before anything actual happened within my router and the errors were all the same.

Appreciate all of the help guys :) But, as it’s working I guess we can chalk it up as resolved?

So now you have Tomato installed and it’s working as expected? Did you leave your router turned on when you left for two hours, or did you turn it off and then on again when you came back?

Flashing the RT-N66U can definitely be painful. I spent a few hours this evening and ultimately it seems like you basically need to wait a good long time and just leave it alone as it goes.

The ASUS tool will upload the firmware and then it will time out saying that it cannot talk to the router. Just let it sit. And then let it sit more. Keep letting it sit until the unit reboots itself and powers back on (Wifi lights being on is basically the indicator). Apparently (via lots of googling) this is due to the filesystem writing to flash really, really slowly. If you interrupt the process (I did more than once, thinking it was simply stuck) then you basically make the next try take even longer.

I’m using the latest Shibby build of Tomato and it definitely needed me to reset the NVRAM afterwards, otherwise it basically didn’t “see” the WAN side of things (couldn’t get a DHCP address and such).

Hi , worked like a charm. Little hint, especially for all Mac users for whom ASUS doesn’t provide the Firmware restoration tool: you don’t need that tool.
Complete steps 2 above. Then give your computer a fixed IP address of Complete step 3. The Router is then in Firmware Restoration Mode. You can access the router by typing in your Web browser. There, use the Router-integrated function to upload directly the new Firmware of your choice.

Thank you, this is very useful information. If I’d know it was possible to flash the router this way, I probably wouldn’t have referenced using the restoration utility at all.


I’m trying to set up an ASUS RT-N66U. I’ve followed all of the directions, and my browser simply will not connect to the router’s tool.

Any thoughts are much appreciated.

Yes! It was a wild ride.

So, I could only connect to the router when connected via DHCP and while the router was in the normal “on” position…not the recovery mode. Note the router is not connected to the internet.

When I put in the server address of the router I came upon its set-up mode. Go through most of this, but there is a screen where it allows you to set the time zone. By clicking this, you are brought into the advanced settings mode.

In this screen you can upgrade the firmware. Upload the firmware. At this point mine (Sabai OS) could not be uploaded and I was brought to its CFE miniWeb Server. Once again you have the option of uploading firmware.

Turn off the router and put your computer into static ip mode. Restart the router in recovery mode. Now upgrade the firmware and wait for 10 minutes after your firmware has been successfully flashed. Then enable DHCP.

This worked for me. It may or may not work for you. Hopefully it will! Advance at your own risk.

I successfully flashed it with a MacBook Pro using the web utility. Here are some things to note:

– You need to upload the new firmware really, really fast. For some reason, the web utility is disabled after a minute or so. You’ll know it’s not working because your upload hangs for more than 2 minutes.

– After the upload is complete, the router will stop responding. This is perfectly normal, the router is flashing. This takes between 5 to 10 minutes; you’ll know it’s done because the WiFi lights start flashing.

– You need to do the VRAM reset. This is required if you want your router to work as intended.

I have a MacBook Pro running OSX and want to flash my new asus rt n66u router with tomato. Can you give me detailed instructions? or do you know where I can find them.

I followed these directions and i get to step 8, and it seems to get caught in a boot loop ( my computer shows connectivity for a second and can even ping the old IP of the device once, then it reboots and my pc loses connectivity…and repeat)
in case this was part of the waiting for two hours, i let it sit all night (8+ hours) and it was still going this morning.
it seems to be able to get back into recovery mode, so im currently trying to flash the stock asus firmware on it. right now im in the “wait 2 hours” step and it doesnt look like it is boot looping right now…

I just wanted to post an update on my situation.

for some reason, I was trying to flash an older version of the firmware. when I tried the latest version, it took only maybe 30 minutes

I tried flashing the router via tftp and the restore utility five time, each time waiting 10 minutes before power cycling it to no avail. Flashing via tfp is how I’ve flashed all the Asus routers I’ve done in the past, several WL-520gu & RT-N16’s, a WL-500gP V2.

The sixth time I flashed via tftp, got the file uploaded confirmation and went to bed. When I checked the N66U in the morning Tomato was flashed and ready to go!

Moral of the story, flash the router and go to bed and check it in the morning or at least wait until you see a solid power LED and the two wifi LEDs lit.

I think that the firmware restore utility doesn’t work if you had previously changed your LAN’s network address to anything other then the default 192.168.1.x. In my case, I had changed it to 192.168.0.xc and the utility couldn’t connect to the router.

After playing around with this router, I’ve noticed the following:

– I think that the firmware restore utility doesn’t work if you had previously changed your LAN’s network address to anything other the default 192.168.1.x address. In my case, I had changed it to 192.168.0.x and the utility couldn’t connect to the router.

– You have to connect the router directly your PC. If there are other PCs or devices connected to your LAN, the Rescue utility gets confused and warns that it cannot find the router.

– (just a comment) The port LED corresponding to other devices connected to the router continue to indicate active connections when the rescue mode is active.

this worked absolutely perfect for me. first try. one problem though, my router’s page is in polish? i have to get chrome to translate it for me. which i hope wont be problem. i chose the aio version

Hi I’ve flashed and my router page is in polish as well.I can’t connect to the internet wirelessly .please help .thanks

To people who are getting Polish pages: Are you sure you downloaded the English version? There are two versions on Shibby’s site, one Polish and one English; The Polish version is in the directory ending with -PL, the English version in the directory ending with -EN.

Vegard how do I revert to the original settings to reflash in English …. Do the flash process again downloading the English version.
But I can’t get internet with the Ethernet cable or wirelessly so can’t download the English version .

Since you see the Polish interface, the router should be functioning properly. Make sure your Ethernet card asks the router for an IP address (DHCP) and that the card is not assigned to a static IP. Make sure the Ethernet cable from your internet modem is connected to the WAN port on the router. Make sure your Ethernet cable from your computer to the router is connected. On Wireless, are you able to connect to the router but not get an internet connection, or are you not able to connect to the router via Wireless at all? Make sure your wireless network card also asks the router for an IP address (DHCP) and that the card is not assigned a static IP.

I did all this below from Mike Jones and add my few observations:

1. I did all these below.
2. I did not see any warning about error firmware.
3. After I am done with Step 4 below, I plug in my hot WAN into it and wait. Few minutes later I use the address on #4 and it work.

(From Mike Jones)

A few points in the guide are wrong

1.To upload the firmware you need to hold down the reset button push the power switch on (while holding down the reset switch down) untill the power light starts flashing on and off.

2.Then you can leisurely go to your pc and use the ASUS upload utility to load the firmware.

3.To access the web interface after installing the firmware the Nvram must be cleared first. You do this by Pressing and hold the WPS button (on the back) while plugging in the power cable. Hold for 30 seconds and release the WPS button. It will now reboot attempt to access the web interface on L:root PW:admin


I did follow the instructions for my new RT-N66U (B1) but to no avail. I use a windows xp virtual machine on my laptop to start the Firmware Restoration utility but when I put the router in
emergency mode nothing happens. The LED that used to be blinking stops and goes away.
I let it go for more than 1 hour and still nothing happens. I double checked that I can access the router from the windows vm in ‘normal’ mode, both from the wireless and Lan. The router is not connected to Wan, and my laptop has only one interface configured (manually at
Any ideas what’s happening?

Thanks to everyone on here for posting.

I just flashed my RT-66U with tomato-K26USB-1.28.RT-N5x-MIPSR2-115-AIO-64K.trx for a MAC on Mavericks using Safari.

Worked first time – took about 20 minutes..!

following the directions above i successfully flashed my N66U router. the error message (same as the screenshot ) came but i just waited for another 10 minutes ,and sure enough the router rebooted and i was able to connect to it after erasing the NVRAM.
thank you

To be honest, I never actually used the stock ASUS firmware, I just bought the router and immediately flashed it with Tomato. So I don’t know if it’s actually better, but my general experience with routers is that custom firmware is always better than the stock firmware.

Just wanted to say thank you for this guide! Your instructions were very clear, and I was especially grateful for the note to let the router do its thing if it hung a bit in step #8. That was exactly what mind did, and when it finally did reboot Tomato was running on my router.

Thanks again!

Folowed all instruvtions to the letter.
halfway (around 45%) the upload of the tomato stopped, and i got a message.
Waited a little and tried to upload again, but got the message that the router is not in recue mode.
Turned it off and on again, but i’m afraid its fried now.

Is there something i can still do to save it?

Did you note the message? It might have contained important information. A failed flash doesn’t necessarily mean that the router is fried. Try to restart the process from step number 3 in the guide and see if it helps.

Thank you for this article. In step 8 you state “The solution is to just wait, but it’s not clear how long you have to wait. ”

The answer is about 15 minutes. Mine was ready 12 minutes after I got the error.

I just flashed my router – with success – from lastest stock firmware to latest Shibby.
I used the recover webserver approach as described earlier in the thread.
I also erased NVRAM from the same interface.

I had to wait for 15-20 minutes – so patience is the key!

Thanks for the guide…


1. I can’t find a shibby firmware file for the RT-N66u with 64k in the file name. I have this one . Is this good enough?

2. Should I place this file into a USB drive and plug it into the router?

I just finished flashing my router using these instructions. Thanks! However, I think step #3 could be further improved by skipping that first bit — and simply provide instructions to isolate the router by connecting it directly to a computer using one of the LAN ports and not the uplink port. I’d also include steps on how to assign a static IP to the host. Making these changes to #3 would make the process more reliable and eliminate potential complications, such as the restoration utility not being able to find the router.

I’ve added a note that a LAN port on the router has to be used, not the WAN port. Adding instructions on how to assign a static IP to the host is a good idea, but how this is done varies a little across OSes and versions of OSes, and I doubt that I will get it right for every OS.

If the only difference is the color of the router, I’d assume you can use the same instructions. But there’s a good chance there are also hardware differences between the two models, so you should do some initial research on the Internet before you try.

I don’t know the technical reason why, and it might be that it’ll work using the internal firmware update. But I’ve not tested, so you’d probably be safer following the guide as it stands.

Thank you for posting this. Followed the steps from another site, but it didn’t mention that the firmware utility error message after hitting 100% of the system restore means to wait and be patient. Ended up flashing it twice and couldn’t get it working. You post mentioned the 15-30 min wait and to watch for the WiFi light to be lit. Waiting about 15 mins and boom, all is good. Thanks again.

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