Firstly there are vast online communites whit howtos on install ing various firmware and linux distros this is merly my small how I install Debain onto mine.
Put into upgrade mode
Turn off the slug and while holding the reset key on the back turn it on. After a while you can see the orange light will become red. At that time immediately release reset key.You must be seeing a red light blinking telling you that you did it right :).
Getting The Firmware
The Windows Way
Download the firmware http://www.everbesthk.com/8-download/sercomm/firmware/NU54/Upgrade_207_XP.zip After downloading, open the zip file and run `Upgrade_207_XP.exe. This will install the utility. It will show up in the Start menu, under Programs | Ugutil, as Upgrade Utility.
The Linux (best) way
Download upslug2 from http://trac.nslu2-linux.org/upslug2/browser/trunk
After you have downloaded the source code, use GNU autotools (i.e. autoconf and automake) and GCC to build upslug2:
Getting The Debain Image
Download the latest debian file from http://www.slug-firmware.net/d-dls.php
I got Debain/NSLU2 (armel) 5.0.3 Stable Release.
Installing The Image
Now my slug already had openslug firmware on it and when I did the debian flash it failed so to make it work I had to revert to the stock linksys firware and then install the debian one.
From my linux box that I installed upslug2 onto I ran
upslug2 -i di-nslu2.bin
This software automatically finds your slug and installs the image (obviouslt if you have more than 1 on your network problems will arise).
*NOTE* I highly recomment that you do any image upgrades via a WIRED network due to the possible packet loss that can occur via WIRELESS networks, better still connect your PC and SLUG firectly together using a X-OVER cable.
Once the program outputs Rebooting… done the box will reboot
After you have flashed the debian-installer image, your NSLU2 will boot and start the Debian installer. Since the NSLU2 does not have any IO device, SSH will be used for the installation. The installer will bring up the network, start the OpenSSH server and allow you to connect to the device using SSH. You have to wait approximately five minutes after the debian-installer firmware has been flashed before you can connect, but please be patient as it can sometimes take slightly longer, say 10-15 minutes. When the installer is ready, it will beep three times to indicate that you can now login via SSH using via the username installer and password install
Now you are able to follow the standard on screen prompts and install the OS. Be AWARE that this process does take a few HOURS so make sure you keep your terminal window OPEN otherwise you’ll have to start all over again. Also it’s worth remembering that this is a net install and thus the speed of your connection also has a big part to play in the install time. Unfortunately it’s not an ‘unattended’ install and it does prompt you for various inputs so you will have to keep checking your terminal every so often.