Ubuntu Wiki

This page describes the process of creating a bootable USB key that has multiple ISO images on it. This is especially useful for conferences and testing. The ISOs are simply placed unaltered onto the USB stick and may be directly booted using grub's loopback support. Magic!

Issues

• Grub says: /casper/vmlinuz: file not found after selecting entry.

  • If you get this error, you should rename the grub entry to point at /casper/vmlinuz.efi

Requirements

1. Grub2 (version 1 does not support loopback mode)

2. USB stick (large enough to hold your *.iso files)

Automated Instructions

1. Copy the script below into a file

2. Ensure the file is executable (chmod +x <file>)

3. Insert a USB stick

• NB: All data on your stick will be lost - if it's important back it up

4. Run it as root (sudo ./<file> <drive>)

•  #!/bin/sh
  
  if [ "$(id -u)" != "0" ]; then
     echo "This script must be run as root" 1>&2
     exit 1
  fi
  
  if [ $# -ne 1 ]; then
          echo "Usage: $0 <drive>"
          exit 1
  fi
  
  DISK=$1
  
  echo "Ensuring device is not mounted"
  for i in `ls -1 ${DISK}*`; do 
          umount $i > /dev/null 2>&1
  done
  
  echo "Erasing old partition information"
  dd if=/dev/zero of=${DISK} bs=1024 count=1024 > /dev/null 2>&1
  
  SIZE=`fdisk -l $DISK | grep Disk | awk '{print $5}'`
  
  CYLINDERS=`echo $SIZE/255/63/512 | bc`
  
  echo "Creating partitions"
  echo ",,,*" | sfdisk -D -H 255 -S 63 -C ${CYLINDERS} ${DISK} > /dev/null 2>&1
  
  echo "Formatting disk"
  mkfs.ext4 -L "MultiBoot" ${DISK}1 > /dev/null 2>&1 
  
  echo "Mounting device"
  if [ -b ${DISK}1 ]; then
      mount ${DISK}1 /mnt > /dev/null 2>&1
  else
      echo "ERROR: Can't find ${DISK}1"
      exit
  fi
  
  ANSWER=0
  while [ $ANSWER -lt 1 ] || [ $ANSWER -gt 3 ]; do 
          echo "Is your machine an x86 or AMD64 one?"
          echo "1. i386 (32bit)"
          echo "2. amd64 (64bit)"
                  echo "3. None (do not download any *.iso files)"
          echo -n "> "
          read ANSWER
  done
  
  mkdir /mnt/iso
  cd /mnt/iso
  
  if [ $ANSWER -eq 1 ]; then
          echo "Fetching i386 isos"
          wget http://releases.ubuntu.com/hardy/ubuntu-8.04.4-desktop-i386.iso
          wget http://releases.ubuntu.com/jaunty/ubuntu-9.04-desktop-i386.iso
          wget http://releases.ubuntu.com/karmic/ubuntu-9.10-desktop-i386.iso
          wget http://releases.ubuntu.com/lucid/ubuntu-10.04.1-desktop-i386.iso
          wget http://releases.ubuntu.com/maverick/ubuntu-10.10-desktop-i386.iso
  elif [ $ANSWER -eq 2 ]; then
          echo "Fetching amd64 isos"
          wget http://releases.ubuntu.com/hardy/ubuntu-8.04.4-desktop-amd64.iso
          wget http://releases.ubuntu.com/jaunty/ubuntu-9.04-desktop-amd64.iso
          wget http://releases.ubuntu.com/karmic/ubuntu-9.10-desktop-amd64.iso
          wget http://releases.ubuntu.com/lucid/ubuntu-10.04.1-desktop-amd64.iso
          wget http://releases.ubuntu.com/maverick/ubuntu-10.10-desktop-amd64.iso
  elif [ $ANSWER -eq 3 ]; then
          echo "Not downloading ISOs"
  else
          echo "ERROR: Unknown system type"
          exit
  fi
  
  echo "Writing rebuild script"
  cat <<-EOD >"/mnt/rebuild"
  #!/bin/sh
  
  here=\`dirname \$0\`
  case "\$here" in
      /*) 
          ;;
       *)  
          here="\`pwd\`/\$here" ;;
  esac
  
  for iso in \`cd \$here && ls -1 iso/*.iso\`
  do
      title=\`basename "\$iso" .iso\`
      file="/\$iso"
      cat <<-EOE >>"\$here/boot/grub/grub.cfg"
  menuentry "\$title" {
    loopback loop \$file
    linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=\$file noeject noprompt quiet splash --
    initrd (loop)/casper/initrd.lz
  }
  EOE
  done
  EOD
  
  chmod +x /mnt/rebuild
  
  echo "Installing grub to device"
  sudo grub-install --no-floppy --root-directory=/mnt ${DISK} > /dev/null 2>&1
  
  if [ $ANSWER -ne 3 ]; then
          echo "Rebuilding grub.cfg"
          /mnt/rebuild
  fi
  
  echo "Unmounting"
  cd - > /dev/null 2>&1
  sync;sync;umount /mnt

Manual Instructions

This is the detail step by step of how to make a multiple Ubuntu install USB stick.

1. Prepare a blank usb stick. I have two, 4G and 8G any size should do.
2. fdisk it and make a primary partition cover all the storage.

   • Command (m for help): p
     
     Disk /dev/sdc: 4043 MB, 4043308544 bytes
     125 heads, 62 sectors/track, 1018 cylinders
     Units = cylinders of 7750 * 512 = 3968000 bytes
     Sector size (logical/physical): 512 bytes / 512 bytes
     I/O size (minimum/optimal): 512 bytes / 512 bytes
     Disk identifier: 0x0002098b
     
        Device Boot      Start         End      Blocks   Id  System
     /dev/sdc1               1        1018     3944719   83  Linux

3. sudo mkfs.ext4 /dev/sdc1 (I tried vfat and ext4, all ok)
4. sudo mount /dev/sdc1 /mnt
5. sudo grub-install --no-floppy --root-directory=/mnt /dev/sdc
6. sudo vi /mnt/boot/grub/grub.cfg and key-in following messages

   • menuentry "Ubuntu 10.04 Desktop i386" {
       loopback loop /iso/ubuntu-10.04-desktop-i386.iso
       linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/iso/ubuntu-10.04-desktop-i386.iso noeject noprompt --
       initrd (loop)/casper/initrd.lz
     }

7. sudo mkdir /mnt/iso
8. sudo cp ubuntu-10.04-desktop-i386.iso /mnt/iso/
9. sudo sync;sync;umount /mnt

Then you can reboot and try it out. Enjoy!

Labeling your Stick

If you are using ext4 for your base filesystem you can label the filesystem so that it will always get mounted at the same place. This is handy if you are commonly adding and removing ISO images from the stick. Simply use e2label to label the stick and it will mount in the same place:

1. sudo e2label /dev/sdc1 multi-iso
2. eject and reinsert the stick
3. df

   • [...]
     /dev/sdc1              3859224   2921048    742136  80% /media/multi-iso

Automatic Rebuild

NB: If you followed the 'Automated Instructions' above, this script is created for you - just run to update (sudo <USB_STICK_MNT_POINT>/rebuild).

If you are going to add and remove ISOs on a regular basis you can add the following script to the disk as rebuild:

•  #!/bin/bash
  
  here=`dirname $0`
  case "$here" in
  /*) ;;
  *)  here="`pwd`/$here" ;;
  esac
  
  for iso in `cd $here && ls -1 iso/*.iso`
  do
          title=`basename "$iso" .iso`
          file="/$iso"
          cat - <<EOE
  menuentry "$title" {
    loopback loop $file
    linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=$file noeject noprompt quiet splash --
    initrd (loop)/casper/initrd.lz
  }
  EOE
  done >"$here/boot/grub/grub.cfg"

Then you can simply add and remove images from the USB stick iso directory and run:

1. sudo /mnt/rebuild