Unslung on the Linksys NSLU2

Unslung

Unslung is one of the user community developed linux-based firmwares that can be loaded on to a Linksys NSLU2 to replace the original Linksys firmware and augment the functionality of the device. Replacing the stock firmware allows you to install optional packages to run services such as network services (DDNS, DHCP, firewall...), web services (web server, mail server, bit torrents, VoIP...) add peripherals (print server, webcam...) and much more. This page is just my personal experience of installing Unslung on my NSLU2 but hopefully someone might find it useful (like me in 12 months time when I've forgotten how I set it up...!).

There is a mountain of documentation to read on Unslung which is initially confusing - where to start? My suggestion (as a recent 1st-timer) is to read the following documents in this order:

The New Users Guide
The Unslung 6.8 README - Found on the Unslung Download Page. Although 6.10 is the latest version of Unslung (very recently released as I write this) it appears most of the good content has been trimmed out of the 6.10 README. When I installed Unslung 6.8 I felt the 6.8 README was the best document I read and it explained the process and the factors to consider very clearly. The differences between 6.8 and 6.10 seem to be minor so I'd recommend a read of the 6.8 README - check it out.
Read around the subject of USB ports, storage and flash devices - I decided to run Unslung on a 4GB USB memory stick in Disk 2 slot to leave the seemingly more flexible Disk 1 slot free for the printer/scanner. There are quite a few warnings about the limited lifetime of flash devices when used in this way so I may rebuild this system with a hard drive when I figure out how to do it cheaply, silently and without another power adapter plugged into the wall.
The FAQ - see if anything catches your eye in the FAQ topics

Initial Setup

For the first step, the NSLU2 came out of the box and I followed the Linksys quick setup instructions - connect to the LAN, power up and access the device through the web interface. At this point I set the NSLU2 to a fixed IP (e.g. 192.168.1.2) so I knew where to find it if it all went pear-shaped.

Next step was to test telnet RedBoot access as described in the TelnetIntoRedBoot guide. Accessing RebBoot from my linux laptop was easy enough, did a quick test with the version and help commands and then closed the connection with ^] (ctrl-right bracket).

After checking telnet RedBoot access, it's time to replace the Linksys firmware with the Unslung firmware. As this was a first time install on a fresh NSLU2 I used the linksys web interface and followed the instructions in the 6.8 README to the letter.

NB - The latest 6.10 README only describes the installation procedure using the RedBoot Upgrade Mode, I assume this is because this mode applies to both fresh NSLU2s and also previously 'unslung' NSLU2s.

After the Unslung firmware is loaded onto the NSLU2, it's time to actually 'unsling' the NSLU2 - this is the process of copying the root filesystem of the device onto an external drive and configuring the NSLU2 to boot from that drive instead of the original internal location. By moving the filesystem onto an external drive you now have plenty of space to install additional packages for added functionality. Again, I followed the 6.8 README to the letter to unsling to my 4GB USB flash disk (formatting it via the NSLU2 web interface along the way).

The next recommended step is to install OpenSSH so that you can use a secure shell connection to talk to the slug rather than Telnet (remember you're sending your root password over the network in clear with Telnet).

That's it really, pretty simple huh? My next step after doing this was to install CUPS (Common Unix Printing System) to run a print server and start thinking about all the other exciting things I can make it do...!