Multiboot USB drive
A multiboot USB flash drive allows booting multiple ISO files from a single device. The ISO files can be copied to the drive and booted directly without unpacking them first. There are multiple methods available, but they may not work for all ISO images.
Contents
-
1 Using GRUB and loopback devices
- 1.1 Preparation
- 1.2 Installing GRUB
- 1.3 Configuring GRUB
- 1.4 Boot entries
- 2 Using Syslinux and memdisk
- 3 See also
Using GRUB and loopback devices
advantages:
- only a single partition required
- all ISO files are found in one directory
- adding and removing ISO files is simple
disadvantages:
- not all ISO images are compatible
- the original boot menu for the ISO file is not shown
- it can be difficult to find a working boot entry
Preparation
Create at least one partition and a filesystem supported by GRUB on the USB drive. See Partitioning and File systems#Create a filesystem. Choose the size based on the total size of the ISO files that you want to store on the drive, and plan for extra space for the bootloader.
Installing GRUB
Mount the filesystem located on the USB drive:
# mount /dev/sdXY /mnt
Create the directory /boot:
# mkdir /mnt/boot
Install grub on the USB drive:
# grub-install --target=i386-pc --recheck --boot-directory=/mnt/boot /dev/sdX
In case you want to boot ISOs in UEFI mode, you have to install grub for the UEFI target:
# grub-install --target x86_64-efi --efi-directory /mnt --boot-directory=/mnt/boot --removable
For UEFI, the the partition has to be the first one in an MBR partition table and formatted with FAT32.
Configuring GRUB
For the purpose of multiboot USB drive it is easier to edit grub.cfg
by hand instead of generating it. Alternatively, make the following changes in /etc/grub.d/40_custom
or /mnt/boot/grub/custom.cfg
and generate /mnt/boot/grub/grub.cfg
using grub-mkconfig.
As it is recommend to use a persistent name instead of /dev/sdxY
to identify the partition on the USB drive where the image files are located, define a variable for convenience to hold the value:
/mnt/boot/grub/grub.cfg
# path to the partition holding ISO images (using UUID) set imgdevpath="/dev/disk/by-uuid/UUID_value"
Alternatively, use the device label instead of UUID:
/mnt/boot/grub/grub.cfg
# path to the partition holding ISO images (using labels) set imgdevpath="/dev/disk/by-label/label_value"
The necessary UUID or label can be found using lsblk -f
. Do not use the same label as the Arch ISO for the USB device, otherwise the boot process will fail.
To complete the configuration, a boot entry for each ISO image has to be added below this header, see the next section for examples.
Boot entries
It is assumed that the ISO images are stored in the boot/iso/
directory on the same filesystem where GRUB is installed. Otherwise it would be necessary to prefix the path to ISO file with device identification when using the loopback
command, for example loopback loop (hd1,2)$isofile
. As this identification of devices is not persistent, it is not used in the examples in this section.
Arch Linux
monthly release
menuentry '[loopback]archlinux-2014.12.01-dual.iso' { set isofile='/boot/iso/archlinux-2014.12.01-dual.iso' loopback loop $isofile linux (loop)/arch/boot/x86_64/vmlinuz archisolabel=ARCH_201412 img_dev=$imgdevpath img_loop=$isofile earlymodules=loop initrd (loop)/arch/boot/x86_64/archiso.img }
archboot
See also: Archboot
menuentry '[loopback]archlinux-2014.11-1-archboot' { set isofile='/boot/iso/archlinux-2014.11-1-archboot.iso' loopback loop $isofile linux (loop)/boot/vmlinuz_x86_64 iso_loop_dev=$imgdevpath iso_loop_path=$isofile initrd (loop)/boot/initramfs_x86_64.img }
CentOS
Stock installation medium
menuentry '[loopback]CentOS-7.0-1406-x86_64-DVD' { set isofile='/boot/iso/CentOS-7.0-1406-x86_64-DVD.iso' loopback loop $isofile linux (loop)/isolinux/vmlinuz noeject inst.stage2=hd:/dev/sdb2:/$isofile initrd (loop)/isolinux/initrd.img }
Desktop live medium
menuentry '[loopback]CentOS-7.0-1406-x86_64-GnomeLive' { set isofile='/boot/iso/CentOS-7.0-1406-x86_64-GnomeLive.iso' loopback loop $isofile linux (loop)/isolinux/vmlinuz0 root=live:CDLABEL=CentOS-7-live-GNOME-x86_64 iso-scan/filename=$isofile rd.live.image initrd (loop)/isolinux/initrd0.img }
Clonezilla Live
menuentry "Clonezilla Live 2.2.3-25 amd64" --class iso { set isofile="/boot/iso/clonezilla-live-2.2.3-25-amd64.iso" loopback loop $isofile linux (loop)/live/vmlinuz findiso=$isofile boot=live union=aufs config noprompt ip=frommedia toram=filesystem.squashfs initrd (loop)/live/initrd.img }
Debian
Stock install medium
menuentry '[loopback]debian-7.8.0-amd64-DVD-1' { set isofile='/boot/iso/debian-7.8.0-amd64-DVD-1.iso' set initrdfile='/boot/iso/debian-7.8.0-amd64-DVD-1.hdd.initrd.gz' loopback loop $isofile linux (loop)/install.amd/vmlinuz vga=791 iso-scan/ask_second_pass=true iso-scan/filename=$isofile initrd $initrdfile }
Live install medium
menuentry '[loopback]debian-live-7.8.0-amd64-xfce-desktop' { set isofile='/boot/iso/debian-live-7.8.0-amd64-xfce-desktop.iso' loopback loop $isofile linux (loop)/live/vmlinuz boot=live config fromiso=/dev/sdb2/$isofile initrd (loop)/live/initrd.img }
Fedora
Stock installation medium
menuentry '[loopback]Fedora-20-x86_64-DVD' { set isofile='/boot/iso/Fedora-20-x86_64-DVD.iso' loopback loop $isofile linux (loop)/isolinux/vmlinuz noeject inst.stage2=hd:/dev/sdb2:/$isofile initrd (loop)/isolinux/initrd.img }
Workstation live medium
menuentry '[loopback]Fedora-Live-Workstation-x86_64-21-5' { set isofile='/boot/iso/Fedora-Live-Desktop-x86_64-21-5.iso' loopback loop $isofile linux (loop)/isolinux/vmlinuz0 root=live:CDLABEL=Fedora-Live-WS-x86_64-21-5 iso-scan/filename=$isofile rd.live.image initrd (loop)/isolinux/initrd0.img }
GParted Live
menuentry "GParted Live" { set isofile="/boot/iso/gparted-live-0.18.0-1-amd64.iso" loopback loop $isofile linux (loop)/live/vmlinuz boot=live config union=aufs noswap noprompt ip=frommedia toram=filesystem.squashfs findiso=$isofile initrd (loop)/live/initrd.img }
Kali Linux
menuentry '[loopback]kali-linux-1.0.7-amd64' { set isofile='/boot/iso/kali-linux-1.0.7-amd64.iso' loopback loop $isofile linux (loop)/live/vmlinuz boot=live findiso=$isofile noconfig=sudo username=root hostname=kali initrd (loop)/live/initrd.img }
Linux Mint
menuentry "[loopback]linuxmint-201403-cinnamon-dvd-32bit" { set isofile="/boot/iso/linuxmint-201403-cinnamon-dvd-32bit.iso" loopback loop $isofile linux (loop)/live/vmlinuz isofrom=/dev/sdb2/iso/$isofile boot=live live-config live-media-path=/live quiet splash noeject noprompt initrd (loop)/live/initrd.img }
openSUSE
Stock installation medium
menuentry '[loopback]openSUSE-13.1-DVD-x86_64' { set isofile='/boot/iso/openSUSE-13.1-DVD-x86_64.iso' loopback loop $isofile linux (loop)/boot/x86_64/loader/linux install=hd:$isofile initrd (loop)/boot/x86_64/loader/initrd }
LiveCD
menuentry '[loopback]openSUSE-13.1-KDE-Live-x86_64' { set isofile='/boot/iso/openSUSE-13.1-KDE-Live-x86_64.iso' loopback loop $isofile linux (loop)/boot/x86_64/loader/linux isofrom_device=$imgdevpath isofrom_system=$isofile LANG=en_US.UTF-8 initrd (loop)/boot/x86_64/loader/initrd }
Sabayon
menuentry '[loopback]Sabayon_Linux_14.05_amd64_KDE' { set isofile='/boot/iso/Sabayon_Linux_14.05_amd64_KDE.iso' loopback loop $isofile linux (loop)/boot/sabayon root=/dev/ram0 aufs cdroot locale=en_US loop=/livecd.squashfs looptype=squashfs isoboot=$isofile initrd (loop)/boot/sabayon.igz }
Slackware Linux
menuentry '[loopback]slackware64-14.1-install-dvd' { set isofile='/boot/iso/slackware64-14.1-install-dvd.iso' loopback loop $isofile linux (loop)/kernels/huge.s/bzImage printk.time=0 initrd (loop)/isolinux/initrd.img }
SystemRescueCd
menuentry "System Rescue CD 64" { set isofile='/boot/iso/systemrescuecd-x86-x.y.z.iso' loopback loop $isofile linux (loop)/isolinux/rescue64 isoloop=$isofile initrd (loop)/isolinux/initram.igz }
Ubuntu
menuentry '[loopback]ubuntu-14.04.1-desktop-amd64' { set isofile='/boot/iso/ubuntu-14.04.1-desktop-amd64.iso' loopback loop $isofile linux (loop)/casper/vmlinuz.efi boot=casper iso-scan/filename=$isofile locale=en_US.UTF-8 initrd (loop)/casper/initrd.lz }
Slitaz
First, download slitaz iso, then extract somewhere (in this case, /live/slitaz-4.0 on /dev/sda3)
menuentry 'slitaz-4.0 core' { set dir='/live/slitaz-4.0' set root=(hd0,msdos3) set lang='pt_BR' set kmap='br-abnt2' linux ($root)/$dir/bzImage lang=$lang kmap=$kmap rw root=/dev/null vga=normal autologin initrd ($root)/$dir/rootfs4.gz ($root)/$dir/rootfs3.gz ($root)/$dir/rootfs2.gz ($root)/$dir/rootfs1.gz }
Slax
First, download Slax zip (for USB), then extract somewhere (in this case, /live/slax on /dev/sda3)
menuentry 'slax' { set dir=/live/slax set root=(hd0,msdos3) linux $dir/boot/vmlinuz from=$dir vga=normal load_ramdisk=1 prompt_ramdisk=0 printk.time=0 slax.flags=perch,xmode initrd $dir/boot/initrfs.img }
Using Syslinux and memdisk
Using the memdisk module, the ISO image is loaded into memory, and its bootloader is loaded. Make sure that the system that will boot this USB drive has sufficient amount of memory for the image file and running operating system.
Preparation
Make sure that the USB drive is properly partitioned and that there is a partition with file system supported by Syslinux, for example fat32 or ext4. Then install Syslinux to this partition, see Syslinux#Installation.
Install the memdisk module
The memdisk module was not installed during Syslinux installation, it has to be installed manually. Mount the partition where Syslinux is installed to /mnt/
and copy the memdisk module to the same directory where Syslinux is installed:
# cp /usr/lib/syslinux/bios/memdisk /mnt/boot/syslinux/
Configuration
After copying the ISO files on the USB drive, edit the Syslinux configuration file and create menu entries for the ISO images. The basic entry looks like this:
boot/syslinux/syslinux.cfg
LABEL some_label LINUX memdisk INITRD /path/to/image.iso APPEND iso
See memdisk on Syslinux wiki for more configuration options.
Caveat for 32-bit systems
When booting a 32-bit system from an image larger than 128MiB, it is necessary to increase the maximum memory usage of vmalloc. This is done by adding vmalloc=valueM
to the kernel parameters, where value
is larger than the size of the ISO image in MiB.[3]
For example when booting the 32-bit system from the Arch installation ISO, press the Tab
key over the Boot Arch Linux (i686)
entry and add vmalloc=768M
at the end. Skipping this step will result in the following error during boot:
modprobe: ERROR: could not insert 'phram': Input/output error