Asuswrt-Merlin - Custom firmware for RT-AC66U

[RMerlin]

About:
This is a customized version of Asuswrt, the firmware developed and used by Asus on many of their routers.

Currently supported: RT-N66U, RT-AC66U, RT-N16 (Experimental)

The primary goals of this project are to fix bugs, add a few basic features and tweaks to the original firmware. This firmware will try to remain as close as possible to the original firmware. If you are looking for a slew of advanced features, then this project is not for you. Look at TomatoUSB or DD-WRT, two excellent products that might suit your needs better.

If however you prefer something as close as possible to the manufacturer's firmware, then this is for you

Latest release: 3.0.0.3.178.15

Asuswrt-merlin provides the following changes over the original firmware:

• WakeOnLan web interface (with user-entered preset targets)
• JFFS persistent partition
• User scripts executed at init, services startup, WAN up, firewall up and shutdown.
• SSHD (through dropbear)
• OUI (MAC address) lookup if you click on a MAC on the Client list (ported from DD-WRT)
• Optionally turn the WPS button into a radio on/off switch
• Saving your traffic history to disk (USB or JFFS)
• Displaying monthly traffic history
• Cron jobs
• Monitor your router's temperature (under Administration -> Performance Tuning)
• Display active/tracked network connections
• Allows tweaking TCP/UDP connection tracking timeouts
• Various bugfixes: crash issues related to VPN, etc...
• layer7 and cifs kernel modules added
• Optional user-settings for the WAN DHCP client (required by some ISPs)
• Description field added to DHCP reservation entries
• Dual WAN support (both failover and load balancing supported)
• Disk spindown after user-configurable inactivity timeout
• System info summary page
• Wireless client IP and hostname on the Wireless Log page

Download:
You can download it from the Github repo:
https://github.com/RMerl/asuswrt-merlin/downloads

Or from my website:
(Beta release only available on Github at the moment)

The source code including my changes can be found on Github: https://github.com/RMerl/asuswrt-merlin.

Hope you folks like it

 

[RMerlin]

This is the first beta release of Asuswrt-merlin for the RT-AC66U. A few random notes:

The RT-AC66U have a quite different flash memory architecture from the RT-N66U. For starter, two separate flash storage. One 2 MB storage used by the bootloader and by NVRAM (and yes, 64KB is allocated and used). And the second storage is a whooping 128 MB, of which 32 MB are currently set aside for the firmware itself. The kernel contains inactive code that would be able eventually to handle two firmware images in flash. No idea if Asus intends to implement this for the AC66U or for some future device.

The new init code in the kernel had no JFFS partition allocated. I had to implement it (based on the N16/N66U code), allocating 32 MB out of the unused 90+ MB. Allocating more than this would make little sense, and exhibited a few random issues when I tested it. Still, I believe that 32 MB of JFFS should be more than enough, considering that partition should mostly be used for storing scripts, kernel modules, etc...

I re-enabled the output power option that Asus had mistakenly disabled (from what I see in the code, it was a genuine mistake).

VPN + network GRO support don't seem to cause router crashes like the N66U does. Possibly related to the newer (version 6.x) driver? Not sure. So for the time being, I have kept GRO support enabled.

Interesting bit: temperature is about 2C lower on the AC66U than it was on the N66U. Better heatsink perhaps?

For the rest, basically all the same features as the N66U are present.

Please let me know how this build is working out for you. I've been using the AC66U as my main router for a few days now, with no issue so far.

 

[Chuck_IV]

Thanks Merlin.

I loaded it up on my RT-AC66U without issue and while I haven't been using it long(an hr or so) everything seems great so far. I'll report if I see any issues.

 

[R3S2a7i6]

Hi Merlin, Thank you ! Downloading now...will report if there are any issues. With kind regards,

 

[Andre.R]

Thank you, I can now purchase the ac66u

I am currently running ddwrt on a buffalo router. I have been looking for a way to have a usb 3g/4g wan failover with my current setup.

the asus setup will give me eveything i need.

I know there are slight issues with the failover needing a router reset to flip back when the primary wan is restored, but It's not a deal breaker because its for surveillance/automation reasons.



Thanks.
Andre

ps check your paypal

 

[RMerlin]

ps check your paypal

Got it - thank you

 

[R3S2a7i6]

Hi Merlin, I noticed that enabling the WPS button on the router to turn on/off the Radio, in radio off mode, does not switch off the 5G blue light on the router, But it does disable both 2G & 5G wireless access. If 2G & 5G are manually disabled via the UI, it works fine. With kind regards,

 

[alternety]

Merlin - As you get more familiar with the AC version, could you venture an opinion as to whether or not it would be worth the effort to sell an existing RT version to get an AC version. Two points so far appear to be a bit cooler operating temperatures and native support for 64K nvram. Plus more overall memory. If you could just keep it in mind and let us know. Maybe the AC is the RT C or B2.

 

[RMerlin]

Merlin - As you get more familiar with the AC version, could you venture an opinion as to whether or not it would be worth the effort to sell an existing RT version to get an AC version. Two points so far appear to be a bit cooler operating temperatures and native support for 64K nvram. Plus more overall memory. If you could just keep it in mind and let us know. Maybe the AC is the RT C or B2.

It depends on what you intend to do. DD-WRT and Tomato support will be quite tricky to do with the AC66U due to the split flash architecture, so if you intend to eventually go with DD-WRT or Tomato (which would be the only reason why "native" 64K NVRAM might be an issue), then you should probably wait and see whether the devs are able to fully support the AC66U. Otherwise, it does not matter how the N66U implements the 64K nvram support, it works just fine the way Asus implemented it (and which will be available in the official firmware in the near future).

Both routers have the same amount of memory - it's the flash storage that is larger (128 MB + 2 MB vs 32 MB). I doubt the N66U will run out of space anytime soon with 32 MB.

If you intend to keep the router for many years and eventually go down the 802.11ac path, it might be worth trying to resell your N66U while it still has excellent street value, and grab an AC66U instead. If you intend however to run Tomato or DD-WRT, the N66U is a much safer bet at this time.

 

[RMerlin]

Hi Merlin, I noticed that enabling the WPS button on the router to turn on/off the Radio, in radio off mode, does not switch off the 5G blue light on the router, But it does disable both 2G & 5G wireless access. If 2G & 5G are manually disabled via the UI, it works fine. With kind regards,

This seems to be a regression over the N66U, I'll take a closer look at it. Could be related to the ac support perhaps.

 

[icemankent]

RMerlin,

How does your build improve the buggy QoS that ASUS has crippled their routers with ?

I have read that in the stock firmware, as soon as you turn QoS ON, throughput drops significantly.

Is this the case with your builds as well, or have you fixed it - and if so, can you describe the fix/operation ?

Thanks !

 

[RMerlin]

RMerlin,

How does your build improve the buggy QoS that ASUS has crippled their routers with ?

I have read that in the stock firmware, as soon as you turn QoS ON, throughput drops significantly.

Is this the case with your builds as well, or have you fixed it - and if so, can you describe the fix/operation ?

Thanks !

I just spent the evening looking into this. The problem isn't actually caused by enabling QoS, but by disabling HW acceleration (which enabling QoS will do). As soon you disable HW acceleration, wifi performance drops to 200 KB/s here. HW acceleration should in theory only affect packet filtering, so I'm assuming something else is at play here, which ends up being bypassed when the ctf kernel module gets used.

I can't figure out the cause unfortunately, so we'll have to hope that Asus will fix it in the near future. This pretty much makes this router half useless if you need QoS, I had to revert to my N66U as my main router for now.

There also seems to be another issue with enabling/disabling the 5G led after the router is done booting. Not sure why, looks to be a low-level issue.

I think this router's firmware still has quite a few rough edges. Hopefully Asus will come around and solve most of these issues.

 

[R3S2a7i6]

Hi Merlin,

It’s been just over 44hrs, using your AC66U custom 3.0.0.3.164.15 Beta build, the router is stable / rock solid with heavy wired and wireless traffic. Also with your build, AP mode, unsecured wired and wireless connection issue has been resolved.

However, the known QOS and the 5G led issues are still there….

Looking at the UI Tools page, I note the temperature readings for 2.4Ghz: 51°C and 5Ghz: 58°C Is this normal? What readings are you getting?

With kind regards,

 

[RMerlin]

Hi Merlin,

It’s been just over 44hrs, using your AC66U custom 3.0.0.3.164.15 Beta build, the router is stable / rock solid with heavy wired and wireless traffic. Also with your build, AP mode, unsecured wired and wireless connection issue has been resolved.

However, the known QOS and the 5G led issues are still there….

Looking at the UI Tools page, I note the temperature readings for 2.4Ghz: 51°C and 5Ghz: 58°C Is this normal? What readings are you getting?

With kind regards,

5G LED issues might be resolved in a newer firmware release from Asus from what I saw in the build 178 sources they recently released for the DSL-N55. No idea on the HW Acceleration + Wifi issues, I will have to see if these new sources also resolved the issue.

Your temperature look normal to me. Mines will vary between 53C and 56C depending on the weather (and my RT-N66U could reach as high as 58C). The chips can handle it without any problem.

 

[grinmaul]

I am going to pick up an AC66 next week some time, was wondering if your firmware has ip based bandwidth tracking? if not could it be added?

it is really the only reason i would go to a tomato version but i really only need that one feature

 

[RMerlin]

I am going to pick up an AC66 next week some time, was wondering if your firmware has ip based bandwidth tracking? if not could it be added?

it is really the only reason i would go to a tomato version but i really only need that one feature

No, and it's not something on the agenda at this time, sorry.

You might be able to install additional software yourself that could achieve the same result, through optware. I also remember seeing a bandwith monitoring script (bwmon if I remember) written for DD-WRT and Tomato which could also be reused on this router.

 

[RMerlin]

3.0.0.3.178 RM15 is now available! Grab it off Github (I will upload it to my website later).

This is the first official release I make for the RT-AC66U. This version is based on 3.0.0.3.178 (Asus having pulled the broken 3.0.0.3.182 release from their website).

Some noteworthy fixes Asus has done on 178 include the 5G LED not turning itself off when the radio is disabled, and the radio scheduler issue where the radio wouldn't turn itself back on when appropriate.

The QoS/CTF and Wifi issue however is not fixed yet. Asus is aware of the issue and are working on it, so it's just a matter of patience.

 

[j_s]

Your temperature look normal to me. Mines will vary between 53C and 56C depending on the weather (and my RT-N66U could reach as high as 58C). The chips can handle it without any problem.

My RT-AC66U (wall-mounted) has typical temperatures of 56C (2.4 GHz) and 62C (5GHz). The room temperature is fairly stable at about 21C.

With 5GHz disabled the 2.4GHz temp drops to about 51C.

Could there be a problem with having the unit wall-mounted?

Running firmware version 3.0.0.3.164.15 (Merlin build).

 

[RMerlin]

My RT-AC66U (wall-mounted) has typical temperatures of 56C (2.4 GHz) and 62C (5GHz). The room temperature is fairly stable at about 21C.

With 5GHz disabled the 2.4GHz temp drops to about 51C.

Could there be a problem with having the unit wall-mounted?

Running firmware version 3.0.0.3.164.15 (Merlin build).

Could be. I only tested my two routers flat on a wooden shelf, or standing using Asus's stand, and in both case my temperature never exceeded 58C during the hottest days of summer.

Could also be because you use your wifi more heavily than I do, as it's mostly used by my Android tablet, and some light traffic on the laptop when I use it for development.

I'm also using the stock power output (80 mw).

In any case, you're still safe. If I remember, the chip can hit as high as 70C or 80C, at which point it will start throttling down to prevent damage.

 

[octopus]

Just notice this, if the chip can be used with 70-80 grd then you must consider what ambient temp you have. Eg 25grd ambient then temprise only can exceed 45-55grd temprise.

octopus