Starting the Ubuntu Network Install from a USB Drive

Starting the Ubuntu Network Install from a USB Drive USB drives can be used to simplify system installations. For example, if the computer can boot from a USB drive, then you can use it to launch a network installation.

Configuring the thumb drive for use as a network installation system requires some simple steps:

1. Plug in the USB drive. If it mounts, unmount it.

2. Download the boot image. There is a different boot image for every platform. Be sure to retrieve the correct one for your Ubuntu release. For example, for Hardy Heron (8.04 LTS), use:

wget http://archive.ubuntu.com/ubuntu/dists/\
hardy/main/installer-i386/current/images/netboot/boot.img.gz

3. The boot image is preconfigured as a USB floppy drive. Copy the image onto the thumb drive. Be sure to specify the base device (for example, /dev/sda) and not any existing partitions (for example, /dev/sda1).

zcat boot.img.gz > /dev/sda

4. Use sync to ensure that all writes complete, and then eject the thumb drive:

sudo sync; sudo eject /dev/sda

Now you are ready to boot off the thumb drive, and the operating system will be installed over the network.

Every PC that I tested with Boot from USB support was able to run the default network installer: boot.img.gz. However, since USB support is not consistent, this may not necessarily work on your hardware. If you cannot get it to boot, then make sure your BIOS is configured to boot from the USB drive, that it boots from the USB before booting from other devices, and that the USB drive is connected to the system. If you have multiple USB devices connected, remove all but the bootable thumb drive.

Source of Information : Wiley Ubuntu Powerful Hacks And Customizations