Asus RT-N66U Router

[cyclones]

Hey Guys, I have a Asus RT-N66U router that has been being a pain in the @$$ real lately. After doing some firmware upgrades, I try and power the router on and the blue power light comes on steady lit and then also port 1 activity light is blinking which is plugged into my laptop. I can't for some reason get a ping AT ALL to the router. I tried giving my laptop a static IP address and doing a ping and trying to access the router homepage all with no luck.. I reset the router back to its defaults (i think) and still had no luck locally accessing the router.. Any help at all guys?
Thanks in advanced!

 

[carnageX]

Did you reset it by doing a 30-30-30 reset?

Hold the reset button for 30 seconds while powered ON.
UNPLUG the router from power while STILL holding the reset button for 30 seconds.
PLUG IN the router while STILL holding the reset button for 30 seconds. After this, you should be able to release the reset button and wait for it to finish booting fully, and then try to access it via it's default settings.

 

[Apokalipse]

I have had to recover an RT-N66U before from a bad flash, and I'll explain what happened it my case, which sounds possibly like what happened in your case.
Basically, the RT-N66U originally released with 32K NVRAM (where it stores the current configuration), but they later upgraded it to 64K. The hardware doesn't change, only the firmware.
The firmware actually consists of the main router OS, as well as a CFE, which is basically a small recovery OS/boot loader.
The NVRAM is stored in the CFE, and normally when you flash the router it doesn't get touched.

In my case, I got a router with 64K NVRAM (and you almost certainly did too, since 32K NVRAM only came with earlier routers).
But if you flash the main firmware with one designed for 32K NVRAM, it'll think the NVRAM is corrupt, and reset it every boot.
Using a serial console connection (if you open the router up, you'll see four pins which are used for this), I saw that it was trying to load ethernet drivers for a WRT54GL, which of course doesn't work on the RT-N66U. So the ethernet ports won't work, but otherwise the firmware does boot.

But essentially, the way to recover this router is to fully erase the NVRAM, and then to only let the CFE boot, not the main firmware, because if it does it'll just reset the NVRAM with improper values and the ethernet ports will continue to not work.

To do this without using a serial console cable, you need to:
* Download a TFTP server program. The Asus Firmware Restoration Utility is essentially just that, and is easy to use.
* Download new firmware, and make sure it's designed for 64K NVRAM. I used TomatoUSB firmware (this is currently the latest version for the RT-N66U).
* Set a static IP address of 192.168.1.2
* With the router powered off, hold down the WPS button, and then turn it on. This will make it reset the NVRAM.
* After resetting the NVRAM, without releasing the WPS button, turn it off, so it doesn't try to boot from the main firmware.
* Make sure your LAN cable is plugged in, and get your TFTP server ready. With the Asus Firmware Restoration Utility, make sure it's it's one click away from uploading the new firmware (it times out if it doesn't begin uploading after a short while).
* Then, press the reset button and turn it on, and immediately start your TFTP server. Your router should then download and flash the new firmware.
* Wait until it's done flashing. It's probably best if you give it a good few minutes at least. Then reboot it.

 

[cyclones]

Thanks for the great response Apokalipse! I was messing around with it last more night and found that I had to boot the router into recovery mode, loaded the stock asus firmware and it worked! However, I was trying to load the DD-WRT firmware onto it but can't get it working with it for some reason. I'll have to try that Tomato USB firmware.

 

[cyclones]

I tried doing the method you mentioned above but using the DD-WRT firmware and the Utility said it was done and to wait for the router to reboot. I waited about 10 minutes and it didnt look like it reboot. I manually rebooted but but only get the power light and port 1 blinking.. and normally with wifi lights would come on if it was functioning correctly.. Hmm.

 

[Apokalipse]

Which DD-WRT firmware are you trying to use?
I think TomatoUSB is designed to have its own NVRAM separate from the CFE's NVRAM, so it doesn't matter whether you get a TomatoUSB version uses 32K or 64K NVRAM, they'll both work.
But DD-WRT uses the NVRAM built into the CFE, so if the router has 64K NVRAM, you need to get a DD-WRT build made for 64K NVRAM.

 

[cyclones]

This is the guide that I am trying to follow: DD-WRT on the Asus RT-N66U – with 64K CFE | Charles Wilkinson So I got the original asus firmware loaded and then loaded the Merlin firmware which worked just fine.. It said in the guide that you need to upgrade your CFE, which is explained here CFE bootloader update - SmallNetBuilder Forums . So currently, I have a SSH session open to the router and am trying to get the file on a remote server, but getting a 'wget bad address' and it doesn't connect to the site (see screenshot). Do you know how I would do a local copy into the router?? Someone said they had to use a SCP command. Thank you!

 

[Apokalipse]

That's only for upgrading your CFE from 32K NVRAM to 64K NVRAM. Only early released RT-N66U's had 32K NVRAM.
You can find out what CFE version your router has by typing:
cat /dev/mtd0ro | grep bl_version
If it has version 1.0.1.3, that means it already has 64K NVRAM, and you don't need to perform a CFE upgrade.

If you've flashed to a not old asus stock firmware, it should have upgraded it to CFE 1.0.1.3 anyway if it didn't already have it.

 

[cyclones]

Ok. I just got down loading the latest official asus firmware on it and then did a telnet session and checked the CFE version and its 1.0.1.2.. I tried loading the dd-wrt.v24-18702_NEWD-2_K2.6_big_RT-N66U.trx on it and it worked, but when I tried saving settings on the routers homepage.. it would never save them on any page so I figured something got screwed up somewhere along the line... :/ Am I using the correct DD WRT version or should I be using something else?

 

[cyclones]

Also, the HW version of my router is B1 is that helps with anything