How to Waste the Day

I received a new antenna from the WISP owner. The previous antenna uses 2.4 GHz and the new antenna uses 5 GHz. The owner wanted to move me to a different frequency and access point (AP) to help reduce congestion on the system.

The new antenna worked fine. I wanted to tinker some with the 5 GHz wireless on the router. Partly to ensure I was not using the same channel but also to see if I could improve the connection. After I finished testing I decided to restore my settings from backup because I did not keep notes about what I had changed.

In the middle of the restore the web interface froze.

As always, I used an ethernet connected computer to perform the update. In all the years of using DD-WRT I had never seen this happen. I was uncertain whether I had bricked the device.

I could not access the web browser interface. I resorted to pressing the reset button. I then could access the web interface but I could not log in. I also tried the default account name and password. Oddly, eventually I tried a screwball combination of the new account name and the default password.

I logged in.

I restored the previous backup and this time the restoration succeeded.

About two weeks later I decided to update the firmware. I had been using version 30826. I had not updated since last year. Of course, everything with DD-WRT is beta. There has not been an official release in many years and likely never will. Not thinking, I attempted to install the latest version. I should have known better.

The web interface dialog showed a successful update and the router rebooted. Then the web interface froze. I waited a long five minutes. I tried cycling power but my computer could not connect and the web interface page never returned. I was fearful that this time I had really bricked the router.

I powered on my older Linksys WRT54GL router. Nice that I had a spare router. Not nice that I had ignored the router and not updated the configuration since I started using the Asus router. The configuration was outdated, especially now with the new WISP antenna. I had enough notes and screen captures of the Asus configuration that I was able to get the Linksys functional again. At least I could surf the web to look for help.

Eventually I was able to perform a full 30-30-30 reset on the Asus. I discovered I was not performing the procedure correctly. While pressing the reset button, power needs to be cycled by pulling the power cord and not toggling the device power switch. The steps that worked for me:

1. Remove all ethernet cables.
2. Power on the device.
3. Press and hold the reset button for 30 seconds.
4. Pull the power cord.
5. Continue holding the reset button for another 30 seconds.
6. Restore the power cable.
7. Continue holding the reset button for another 30 seconds.

This 30-30-30 procedure does not require three hands but is awkward.

I had learned that if this procedure is successful that the power LED will flash in a 4 second cycle. I saw this on my Asus router. A good sign.

Then the additional frustration began. The DD-WRT defaults are 192.168.1.1. I do not use that subnet on my LAN. I had to juggle computer settings to connect to the default IP address.

At that point I was able to ping the device’s default IP address of 192.168.1.1. The web interface page was a default Asus vendor page and not a DD-WRT page. At least I had not bricked the device.

Using the Asus web interface I attempted to upload the DD-WRT version I had been using. No luck. Nothing happened.

Digging around the web I found discussions about using some kind of Asus Firmware Restoration utility. I could not find this utility on the Asus web site. Not that the utility would have helped me, being Windows only. I do not have a physical Windows system that can be connected directly to the router.

More digging revealed that this Windows-only utility is little more than a tftp utility. I followed some online instructions to push the 30826 firmware. I did not see any message that the file had been delivered successfully but the tftp command prompt returned with no error messages. I recycled power on the router.

I could again log into the device using DD-WRT.

As expected, everything was set to the defaults. I restored from my most recent nvram backup.

I then discovered that the router’s 5GHz wireless was not working. At all. Some more digging revealed I probably should erase the nvram and revert to a much older version of the DD-WRT firmware. That should reset the 5 GHz options. Then update to the last known working version. Then restore the latest nvram backup. My recovery:

1. I erased the nvram.
2. I flashed the router to version 26339.
3. I verified a normal 5 GHz web page.
4. I flashed to version 30826, the version I had been using.
5. I restored the nvram backup.
6. I verified I could again use 5 GHz.

Keystone Kops.

Lessons learned?

• Like a lot of free/libre software, DD-WRT development is a personal playground.
• Like a lot of free/libre software, DD-WRT quality assurance is not good.
• Don’t be too eager to flash the latest DD-WRT beta firmware.
• Remember that everything with DD-WRT is beta.
• Find a firmware version that works.
• Thereafter avoid the temptation to update.
• Always perform an nvram backup just before flashing even when no configurations have been changed. One reason is to preserve the WAN traffic data.
• Always have a Plan B.

My Plan B is to update and synchronize the Linksys router configuration and grab current screen shots of configuration pages for both routers. I finished that project after fully restoring the Asus router. Both routers now are configured as similarly as possible. Yet I ran into another DD-WRT glitch I had forgotten.

The older firmware version, v24 pre SP2 Build 13064, which has been pre Service Pack 2 for many years — about 10 years, contains a bug where the wireless configuration gets corrupted. I finally dug into this and discovered that updating the firewall rules in Administrations/Commands caused the wireless ruckus. The only way I found to fix the problem is using SSH, nvram set, and nvram commit. Even then the solution seemed hit and miss. High quality software.

This is how a person wastes several hours of life.

Posted: October 30, 2017 Category: Tutorial, Usability Tagged: DD-WRT

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