NSLU2

The goal of this project is to build a small server using a Linksys NSLU2 and Debian.

• a NSLU2
• an USB Stick which will hold the OS (I choose a 4GB “OCZ Rally2”)
• an external Harddisk (I choose a 300GB Samsung and an additional HD box)
• another PC for uploading the firmware
• a wire cutter, in case you own a NSLU2 with a throttled CPU and you want its full speed
• patience

I bought my NSLU2 before Linksys shipped the “un-throttled”¹⁾ version so the CPU runned only at half of its possible speed. To solve this I had to remove a standard SMD resistor from the board.

% cat /proc/cpuinfo
Processor       : XScale-IXP42x Family rev 1 (v5l)
BogoMIPS        : 132.71
Features        : swp half fastmult edsp 
CPU implementer : 0x69
CPU architecture: 5TE
CPU variant     : 0x0
CPU part        : 0x41f
CPU revision    : 1
Cache type      : undefined 5
Cache clean     : undefined 5
Cache lockdown  : undefined 5
Cache format    : Harvard
I size          : 32768
I assoc         : 32
I line length   : 32
I sets          : 32
D size          : 32768
D assoc         : 32
D line length   : 32
D sets          : 32

Hardware        : Linksys NSLU2
Revision        : 0000
Serial          : 0000000000000000

Opening the case was quite easy and only took about 5 minutes (you can do it faster but I wanted to put the case together again ). Removing the resistor is a bit trickier because its really small²⁾. The official tutorial recommend to use a soldering gun but I used a wire cutter instead, I own a really good soldering gun though³⁾. On the left, the naked slug and on the right, the culprit which is about to get removed:

Removing the resistor with the wire cutter took only 1sec :

The result is really impressive :

Processor       : XScale-IXP42x Family rev 1 (v5l)
BogoMIPS        : 266.24
Features        : swp half fastmult edsp 
CPU implementer : 0x69
CPU architecture: 5TE
CPU variant     : 0x0
CPU part        : 0x41f
CPU revision    : 1
Cache type      : undefined 5
Cache clean     : undefined 5
Cache lockdown  : undefined 5
Cache format    : Harvard
I size          : 32768
I assoc         : 32
I line length   : 32
I sets          : 32
D size          : 32768
D assoc         : 32
D line length   : 32
D sets          : 32

Hardware        : Linksys NSLU2
Revision        : 0000
Serial          : 0000000000000000

In order to install Debian on the NSLU2 I had to download the installer image. Note: If you like to use the inbuild NIC you have to choose the unofficial image which includes the ixp400 driver. Furthermore you need upslug2 in order to flash the NSLU2 firmware. If you use gentoo it`s as easy as doing a:

% emerge -a upslug2

To be able to flash the firmware of the slug the box must be in upgrade mode.

Then I used upslug2 to check if it`s able to find the NSLU2.

% upslug2 -d eth0
NSLU2     00:13:10:d6:1e:03 Product ID: 1 Protocol ID: 0 Firmware Version: R23V29 [0x2329]

Ok, found it . Time to put the installer-image on the NSLU2.

% upslug2 -d eth0 -i di-nslu2.bin 
NSLU2     00:13:10:d6:1e:03 Product ID: 1 Protocol ID: 0 Firmware Version: R23V29 [0x2329]
Upgrading LKGD61E03 00:13:10:d6:1e:03
    . original flash contents  * packet timed out
    ! being erased             - erased
    u being upgraded           U upgraded
    v being verified           V verified 

  Display:
    <status> <address completed>+<bytes transmitted but not completed>
  Status:
    * timeout occured          + sequence error detected

  7fffff+000000 ...VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV
Rebooting... done

The slug will beep 3 times as soon as the debian installer is ready to be used. Then log in via ssh using user installer password install. The installation process is as straight forward as a Debian installation could be, no worries here .

Like dolph, I ended up with a few gnome-libs after the installation. Like dolph I got rid of it using:

% aptitude remove gnome-mime-data
% apt-get clean

After updating the package database the usual stuff followed:

• run tzconfig
• dpkg-reconfigure locale (set to en_US.UTF-8)
• set hostname and edited /etc/hosts
• installed some useful tools (iptables, screen, openntpd, zsh)
• checked system time
• changed sshd_config

This is outdated and might not work with recent kernel versions!

There`s currently no truecrypt package available so you have to compile it yourself. In order to do that you`ll need to install some other packages first, namely:

• build-essential (essential C header files)
• dmsetup (low level logical volume management)
• linux-image-2.6 (the kernel source)

% apt-get install build-essential dmsetup linux-image-2.6

Download the truecrypt source at http://truecrypt.org. I put it into /usr/src/. You also have to apply a patch.

% cd /usr/src/
% ls -l
% lrwxrwxrwx  1 root src        19 2007-02-14 22:33 linux -> linux-source-2.6.18
% drwxr-xr-x 20 root root     4096 2007-02-15 22:01 linux-source-2.6.18
% drwxr-xr-x 10 root root     4096 2006-07-03 14:40 truecrypt-4.2a
% wget http://titanic.shipdown.de/pmwiki/uploads/truecrypt-4.2a-Dm-target.c--kernel-2.6.18-and-2.6.19.patch
% patch -p0 truecrypt-4.2a-Dm-target.c--kernel-2.6.18-and-2.6.19.patch

Now lets compile it, this may take a few hours ⁴⁾.

% cd truecrypt-4.2a/Linux
% ./build.sh

After that you can install it using:

% ./install.sh

That´s it.

Here`s a guide about how to compile the latest rtorrent release on the NSLU2. Following this guide I got it working but didn`t use the –enable-align compiler flag (the compilation failed 2 times before while using it). Unfortunately the XMLRPC isn`t working at moment.

% cat /dev/mtdblock* > image

Sometimes it can happen that the NSLU2 refuses to boot into the system. One possible cause for this is when errors in the filesystem are detected during the boot process. By default fsck doesn't attempt to fix possible filesystem errors. You have to enable it in the /etc/default/rcS. To do so just plug the USB-pen into another computer, mount the filesystem and edit the aforementioned file as root.

FSCKFIX=yes

• http://www.nslu2-linux.org
• Dolphs NSLU2
• JPKs NSLU2
• Debian on a emulated ARM system
• Tips on reducing memory usage
• German NSLU2 community wiki