The Death of an EdgeRouter Lite


I’ve been happily using an EdgeRouter Lite (one of the first gen models) for just a touch over 3 years now. Everything worked amazingly well… Until one morning I woke up and my internet was down.

Everything looked normal, lights blinking, no warning lights, etc. After ruling out that my ISP was having issues, I decided to try and connect up my EdgeRouter via a browser. When I did this, I immediately knew there was an issue, I got a server 500 error. Not a DNS error, or some other HTTP error. So I power cycled the router, and same thing.

After digging out a console cable, I connected to the EdgeRouter and there is was… a Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(8,2) error.

I did some quick googling and opened up a case with Ubiquiti support. What was sent to me was a reset and reimaging procedure that can be found here. This is noted as a “last resort” fix that involves reloading the device kernel via TFTP server. Bottom line, it’s a pain in the butt to go through, but I gave it a go…

During the loading procedure, I was able to get the images to load when things were in memory, or limited to small sectors of the boot disk, but once the full image was expanded nothing would work and the images would fail.

After a couple of failed attempts, lots of checksum failures and I/O errors, end_request: I/O error, dev sda, sector 1080144, I decided to rip into the device.

Once I got the device open, the storage is a very cheap USB drive, that is attached via USB to the EdgeRouter mother board. I pulled out that drive and ran some diagnostics, and sure enough, it had a few sectors that were corrupted. Just enough to stop the image from decompressing and functioning. I also tried a few other USB drives, just to see if I could make one work, but nothing seemed to function correctly.


In the end, I decided to order a new EdgeRouter Lite. The newer models are supposedly better designed and don’t have the same USB drive issues as the original models (or so I gathered from doing some reading around the web).

Here are some of the “key” errors that were reported during boot.

  • EXT3-fs (sda2): warning: mounting fs with errors, running e2fsck is recommended
  • SQUASHFS error: squashfs_read_data failed to read block 0x49f1a6d
  • SQUASHFS error: Unable to read metadata cache entry [49f1a6d]
  • SQUASHFS error: Unable to read inode 0x4d1450301
  • VFS: Cannot open root device "sda2" or unknown-block(8,2): error -5
  • Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(8,2)

If you have these issues, for reliability sake, I suggest buying a new unit, they are reasonably priced. Or if your device is still under warranty, I would RMA the device and get a new one.

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