This is an update of the article published before for Debian Sarge. This time, the preparation of an USB device for the installation of Debian Lenny is on the menu. Note that the Ubuntu Startup Disk Creator is not really useful to create a Debian installation device.

Insert an empty(!) USB device of at least 256MB, and look for it in dmesg:

$ dmesg

At the end of the output, it says:

[1922747.172561] sd 29:0:0:0: Attached scsi generic sg4 type 0
[1922747.179137] sd 29:0:0:0: [sde] 1959807 512-byte logical blocks:
(1.00 GB/956 MiB)
[1922747.179629] sd 29:0:0:0: [sde] Write Protect is off
[1922747.179637] sd 29:0:0:0: [sde] Mode Sense: 0b 00 00 08
[1922747.179643] sd 29:0:0:0: [sde] Assuming drive cache: write through
[1922747.182521] sd 29:0:0:0: [sde] Assuming drive cache: write through
[1922747.182532]  sde: sde1
[1922747.205897] sd 29:0:0:0: [sde] Assuming drive cache: write through
[1922747.205908] sd 29:0:0:0: [sde] Attached SCSI removable disk

So apparantly, this device is now known as "/dev/sde". Check if it's automagically mounted:

$mount

If it is (i.e. there is a line that contains /dev/sde), unmount this device first.

umount /dev/sde1

Download the current boot.img.gz from a Debian repository to your home directory. This assumes that you want to use the 64-bits version of Debian.

cd ~
wget ftp://ftp.debian.org/debian/dists/stable/main/installer-amd64/current/images/hd-media/boot.img.gz

Okay, now we need root privileges in order to put this image on the USB device:

sudo bash
zcat ~/boot.img.gz > /dev/sde

Mount the USB device on a mount point. In this case, /mnt/usbdisk will be used for that. Then copy the ISO file to this location.

sudo mkdir /mnt/usbdisk
sudo mount /dev/sde1 /mnt/usbdisk
wget http://cdimage.debian.org/debian-cd/current/amd64/iso-cd/debian-506-amd64-netinst.iso -O /mnt/usbdisk/debian-506-amd64-netinst.iso

You may want to compare the SHA512SUMS of http://cdimage.debian.org/debian-cd/current/amd64/iso-cd/SHA512SUMS with your local version:

$ sha512sum /mnt/usbdisk/debian-506-amd64-netinst.iso

When they match, unmount this USB device, and remove it, because you are now ready to use it to install Debian from it.

$ cd
$ sudo umount /mnt/usbdisk

Original article: http://www.virtualconcepts.nl/2010/09/installing-debian-lenny-from-usb/

Here is a very short (but in my opinion very useful) how-to for creating an USB boot device, which enables you to boot Debian from your memory stick.

We are assuming that your USB device is indicated by /dev/sda, and that you are interested in Debian stable (other distributions are untested, but should work).

First unmount your memory stick.

sudo umount /dev/sda

Now download the boot.img.gz, which is necessary to make your USB device bootable:

cd ~
wget ftp://ftp.debian.org/debian/dists/stable/main/installer-i386/current/images/hd-media/boot.img.gz

Extract this image and write it to your USB device:

sudo zcat ~/boot.img.gz > /dev/sda

Now mount the volume to /mnt:

sudo mount /dev/sda /mnt

In this case a Debian Stable net-install image is used. You may also use a business card iso. Nevertheless, you should be sure to use the same version of the ISO-image as the image.tar.gz that was used before. Download the ISO to the USB device:

cd /mnt/
sudo wget http://cdimage.debian.org/debian-cd/3.1_r3/i386/iso-cd/debian-31r3-i386-netinst.iso

Now you can unmount the volume:

cd ~
sudo umount /dev/sda

You can remove the USB device, and plug it in your new system. Of course you should tell your BIOS to boot from USB. There is a copy of this how-to on our company's website