(Ok) Asus RT-AC66U - Firmware update its security ?

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Hutch and S.
DD-WRT Novice

Joined: 21 Nov 2014
Posts: 6

PostPosted: Wed Nov 26, 2014 12:14    Post subject: (Ok) Asus RT-AC66U - Firmware update its security ? Reply with quote

I have never done updating dd-wrt because I have just installed yesterday ^^ In my example, let's say I used this Firmware:


And for my next update, I will use this manual:


Is it more convenient to choose the setting of picture 1 or picture 2 please (or use the reset with the button on the Asus router is more secure?) ?

The router I use is an Asus RT-AC66U, which works very well with DD-WRT, thank you to the developers... I saw that there is an update here:


Do I have to do right now (for network security?), Or, do I expect? I do not understand the differences between the two versions of firmware that I present here in my message. Is it that each new firmware, it is more prudent to update please? (Although a new firmware arrives approximately every ten days?) Thank you.

(I use Google Translate, sorry for the poorly translated phrases).

Last edited by Hutch and S. on Fri Nov 28, 2014 13:15; edited 2 times in total

Joined: 04 Nov 2014
Posts: 105

PostPosted: Wed Nov 26, 2014 18:25    Post subject: Reply with quote
Rule of thumb: Never update if you don't know what you update for and the system is running stable as it is.

That said - its always a good idea to keep your informations up to date - as in reading the Build-Threads, Changelogs and the like.

Common logical reasons for an update:

  1. Known security holes that are fixed in newer builds

  2. Known instabilities with services that you use which are fixed / improved in the newer builds

  3. New features / performance improvements that you absolutely must have and are working somewhat stable

  4. If you have the time, are willing to use your brains and are willing to help the DD-WRT community by testing Beta-Builds to improve stability - if that point hold true every other point above is invalidated.

Keep in mind an update does not necessarily mean that the quality (as in stability) will improve rather than introduce changes which could (!) lead to more problems than it helps so always be vary and research first as to what Firmware is considered the best up to date - and then try it in your environment thereafter.

Even if a Firmware is considered "the best" up to date for many it doesn't necessarily mean that it must work "the best" in your case since there are many different setups and many different requirements and even when the setups are the same it can result in different outcomes.

In the end you have to take the time to first research and then test what works for you the best.

Cheers! Smile


For example in your case choosing the best Firmware for your AC66U:

Kong 24350 OLDD works the best for me on the AC66U since I'm using it as a Repeater. However while using this build on two different AC66U as a Router I was getting Lag-Spikes on the WAN-Port (meaning the Internet was laggy) so I wouldn't recommend it if the AC66U is your (only) Router.

You could research in the last build threads if someone owning an AC66U flashed these builds and what experiences they made with it BS 25408 works pretty good for me but keep in mind that at the moment ALL newer builds implement an Driver from Broadcom that might lead to unpredictable Reboots while using Mobile Devices with specific WiFi-Chipsets mostly coming from Android and some Apple-Devices as well but not only.

The newer Driver from Broadcom has still not arrived and many are eagerly awaiting the Update (since it 's a big issue for us - but seemingly not Broadcom). Brainslayer will try to contact ASUS to get an Update trough them since they're an official DD-WRT partner and recieve Updates sooner so you might want to wait a bit till the newer Driver Revision arrives and get implemented if you have any of the above Devices (not all of them lead to the issue but many do). Or you could risk it and try it yourself - who knows.

You could also look at TomatoUSB from Shibby which has just released v124. His builds work quite stable on the AC66U with minor hiccups concerning the WiFi-Range (which you can workaround). You can flash forward / backward from DD-WRT to Tomato quite easily - but always do a clean reset if you do so.

Thats all I can say for now.
Hutch and S.
DD-WRT Novice

Joined: 21 Nov 2014
Posts: 6

PostPosted: Thu Nov 27, 2014 5:33    Post subject: Reply with quote
Hello and thank you very much for this long message, which contains many explanations, I understood everything.

Please I do not know where to go to read the build-threads and/or the changelogs ? Does Asus cancel the guarantee of the router if we installed DD-WRT ? (in particular in France ? ). Thank you very much.

Edit :

I have maybe the answer to the question of the guarantee here. The rest I do not know.Thx.

Joined: 04 Nov 2014
Posts: 105

PostPosted: Thu Nov 27, 2014 17:43    Post subject: Reply with quote
Well about the warranty I wouldn't worry to much in the worst case you can restore it via a USB-to-Serial cable but the ASUS-Routers are certainly hard to brick anyway so you can almost always go back to stock before sending it in - no need to tell them that you flashed 3rd-party firmware unless it would help in a special case (which is probably still not a good idea).

For searching recommended builds you should search the forums for existing AC66U threads -
especially large ones and read trough them first. Like this one here:


Only ask for a recommended Firmware after you've read trough them and you just can't find any of them - or at least seem to have invested some time searching for it yourself (that 's the key point). Many times people just register and ask for the "best" Firmware before searching the Forums properly that 's certainly why many of those posts are straight up ignored since they don't even want to spend time themselves but just want others to do the work for them (No thanks!).

Last but not least a recommendation on choosing the Firmware / Build for your AC66U:

As you can see from my linked post in an AC66U thread above and my own findings from the previous post DD-WRT performance for certain parts off the AC66U might be limited (can't confirm that completely but I noticed strange behavior with Pings on the WAN-Port as well on two different AC66U) due to the ASUS-Drivers being compiled for the 2.6 Kernel only and generic Broadcom-Drivers being used in the DD-WRT builds (even Kong ones I guess - at least for the WAN-Part?).

TomatoUSB is using a 2.6 Kernel and - as far as I know -ASUS-Specific Drivers enabling better overall performance on this Device when using the AC66U as a Router (standard scenario).

So your best bet might be any TomatoUSB Build listed here:


(try v123 first and downgrade to v121 or earlier if you have trouble with the WiFi-Performance)

Like the v123 AIO build (VPN builds are smaller but missing some features):


Flash this via the ASUS-Web-Recovery as usual with an NVRAM-Reset-Cycle:

1. Unplug Power-Cable
2. Press & Hold the WPS-Button on the left side
3. Plug Power-Cable back in
4. Hold the WPS-Button for 10s (all LEDs should light up shortly within that time)
5. at 10s press the Reset-Button (right side between USB & WAN-Ports) while releasing the WPS-Button
6. Release the Reset-Button exactly after 5s

Now you should be able to access the Web-Recovery Interface via

If not repeat the above without the WPS-Button (Plug in Cable while holding the Reset-Button for 5s-6s instead) and wait for a few seconds before trying to access the Web-Interface again.

That said support for Tomato can be found here:


Hutch and S.
DD-WRT Novice

Joined: 21 Nov 2014
Posts: 6

PostPosted: Thu Nov 27, 2014 18:38    Post subject: Reply with quote
Once again I understood everything, thank you very much for this help. I do not say that I am going to pass at Tomato at once, because the only thing which slows down me at present and what I do not know where to go to read the threads:

_"Changelogs" of last update of DD-WRT?
_Please I would want read the "build-threads" ?

Thank you very much justyourimage, you have already helped me a lot... See you soon ..

Us, we liked to laugh Smile)

Joined: 04 Nov 2014
Posts: 105

PostPosted: Fri Nov 28, 2014 1:20    Post subject: Reply with quote
Well Changelogs are mostly only available for Stable or Custom Builds like Kong 's.

The general Changesets can be found here (if you can understand the code):


Build Threads are posted in this forum by BrainSlayer like this:


You will find the experience from other users using them with their Router posted there (or not). Beware: It is not for seeking help but only sharing experiences and bug-reports with the build it is made for.

To find them use:


I guess that should answer all your questions. For the rest: Use your own brain. Wink
Hutch and S.
DD-WRT Novice

Joined: 21 Nov 2014
Posts: 6

PostPosted: Fri Nov 28, 2014 13:14    Post subject: Reply with quote
I am a complete beginner with dd-wrt, and the bulb of my flashlight is broken, I came here to look for somebody who had a new bulb to give me, and it is you who gave him(it) to me. I much more see clearly there since your interventions, thank you very much.
Us, we liked to laugh Smile)
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