# Multiboot USB drive

Related articles

- GRUB
- Syslinux
- Archiso

This article or section is a candidate for moving to Multiboot disk images.

Notes: See discussion (Discuss in Talk:Multiboot USB drive#Scope and title)

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.

## Using GRUB and loopback devices

This article or section needs language, wiki syntax or style improvements.

Reason: multiple style issues (Discuss in Talk:Multiboot USB drive#)

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

This article or section needs expansion.

Reason: How much extra space is needed for the bootloader? (Discuss in Talk:Multiboot USB drive#)

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 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. If the ISO images are on the same partition as grub, use the following to read the UUID at boot time:

    /mnt/boot/grub/grub.cfg

    # path to the partition holding ISO images (using UUID)
    probe -u $root --set=rootuuid
    set imgdevpath="/dev/disk/by-uuid/$rootuuid"

Or specify the UUID explicitly:

    /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

This article or section needs language, wiki syntax or style improvements.

Reason: The only boxes used should be code blocks, otherwise the section will be unreadable. Anything else should be plain text. (Discuss in Talk:Multiboot USB drive#)

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.

One can use persistent block device naming like this:

    # define globally (i.e outside any menuentry)
    insmod search_fs_uuid
    search --no-floppy --set=isopart --fs-uuid d6de9100-1981-11e5-9fb9-74867a652f05         # your iso fs uuid here
    # later use inside each menuentry instead
    loopback loop ($isopart)$isofile

Tip: For a list of kernel parameters, see https://www.kernel.org/doc/Documentation/kernel-parameters.txt (still incomplete)

#### Alt Linux

- Initramfs framework: ???
- Live framework: ???
- Init system: ???

    menuentry "[loopback]altlinux-7.0.5-simply-x86_64-install-dvd5.iso" {
            set gfxpayload=keep
    	insmod gzio
    	insmod part_msdos
    	insmod ext2
    	insmod xfs
            set bootpart=uuid:df46d821-e7f9-4e35-bbd2-728bdce8d89a
            set isodir=/boot/iso
            set isofile=altlinux-7.0.5-simply-x86_64-install-dvd5.iso
            loopback loop (${root})${isodir}/${isofile}
            linux (loop)/syslinux/alt0/vmlinuz automatic=method:disk,${bootpart},directory:${isodir}/${isofile} ramdisk_size=183210 changedisk lang=ru_RU splash noeject xdriver=auto quiet=1 showopts
            initrd (loop)/syslinux/alt0/full.cz
    }

#### Arch Linux

Tip: If you want to boot into a 32-bit system, replace `x86_64` with `i686`.

##### monthly release

- Initramfs framework: mkinitcpio (cmdline: [1])
- Live framework: archiso (cmdline: [2])
- Init system: systemd (cmdline: [3])

    menuentry '[loopback]archlinux-2014.12.01-dual.iso' {
    	set isofile='/boot/iso/archlinux-2014.12.01-dual.iso'
    	loopback loop $isofile
    	linux (loop)/arch/boot/x86_64/vmlinuz archisodevice=/dev/loop0 img_dev=$imgdevpath img_loop=$isofile
    	initrd (loop)/arch/boot/x86_64/archiso.img
    }

##### archboot

- Initramfs framework: mkinitcpio (cmdline: [4])
- Live framework: archboot (cmdline: none? RFD)
- Init system: systemd (cmdline: [5])

    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

- Initramfs framework: Dracut (cmdline: [6])
- Installation program: Anaconda (cmdline: [7])
- Init system: systemd (cmdline: [8])

    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
    }

Tip: The boot parameter of second stage install image location `/dev/sdb2` which is used by Anaconda, is similar to fstab's first field (fs_spec), could be replaced with one of:

- `/dev/sdxY`
- `LABEL=MYUSBSTICK`
- `UUID=00000000-0000-0000-0000-0000deadbeef`

For example, `linux (loop)/isolinux/vmlinuz noeject inst.stage2=hd:LABEL=MYUSBSTICK:/$isofile`

##### Desktop live medium

- Initramfs framework: Dracut (cmdline: [9])
- Live framework: fedora livecd-tools (cmdline: none)
- Init system: systemd (cmdline: [10])

    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

Tip: Since 2014.01.05[11], the Arch Linux monthly release contains clonezilla.

- Initramfs framework: initramfs-tools (cmdline: RFD)
- Live framework: Debian Live (cmdline: [12])
- Init system: sysvinit (cmdline: RFD)

    menuentry "[loopback]clonezilla-live-2.2.3-25-amd64" {
    	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

- Initramfs framework: initramfs-tools (cmdline: RFD)
- Installation program: debian-installer (cmdline: exists but missing online documentation)
- Init system: sysvinit (cmdline: RFD)

Tip: To install debian from any stock install medium on a non-optical medium (e.g. usb stick, HDD), it's necessary to use a different initramfs instead of the default one on the installation medium which is located at `(loop)/install.amd/initrd.gz`. If you boot with the default one, the installer will unable to find or mount the proper iso image for installation. Please download the initramfs for hard disk installation from an official mirror site, put it in the same directory with the image file and give it a suitable name (`debian-7.8.0-amd64-DVD-1.hdd.initrd.gz` in this example).

    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

- Initramfs framework: initramfs-tools (cmdline: RFD)
- Live framework: Debian Live (cmdline: [13])
- Init system: sysvinit (cmdline: RFD)

    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
    }

Note: It's also OK to use `findiso=$isofile` instead of the longer `fromiso=/dev/disk/by-.../.../$isofile`. Anyway, using `fromiso=` instead of `findiso=` may speed up the initialization progress because it avoids unnecessary mounting.

#### Elementary OS

- Initramfs framework: RFD
- Live framework or installation program: RFD
- Init system: upstart (cmdline: RFD)

    menuentry '[loopback]elementaryos-freya-amd64.20150411' {
    	set isofile='/boot/iso/elementaryos-freya-amd64.20150411.iso'
    	loopback loop $isofile
    	linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=$isofile locale=en_US.UTF-8
    	initrd (loop)/casper/initrd.lz
    }

#### Fedora

##### Stock installation medium

- Initramfs framework: Dracut (cmdline: [14])
- Installation program: Anaconda (cmdline: [15])
- Init system: systemd (cmdline: [16])

    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

- Initramfs framework: Dracut (cmdline: [17])
- Live framework: fedora livecd-tools (cmdline: none)
- Init system: systemd (cmdline: [18])

    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
    }

#### Gentoo

##### Desktop LiveDVD

- Initramfs framework: genkernel (cmdline: [19])
- Live framework: livecd-tools (cmdline: RFD)
- Init system: OpenRC (cmdline: RFD)

    menuentry "[loopback]livedvd-amd64-multilib-20140826" {
    	set isofile="/boot/iso/livedvd-amd64-multilib-20140826.iso"
    	loopback loop $isofile
    	linux (loop)/isolinux/gentoo root=/dev/ram0 init=/linuxrc aufs looptype=squashfs loop=/image.squashfs cdroot isoboot=$isofile vga=791 splash=silent,theme:default console=tty0
    	initrd (loop)/isolinux/gentoo.igz
    }

Tip: This should also works for minimal medium.

#### GParted Live

- Initramfs framework: initramfs-tools (cmdline: RFD)
- Live framework: Debian Live (cmdline: [20])
- Init system: sysvinit (cmdline: RFD)

    menuentry "[loopback]gparted-live-0.22.0-2-amd64" {
    	set isofile="/boot/iso/gparted-live-0.22.0-2-amd64.iso"
    	loopback loop $isofile
    	linux (loop)/live/vmlinuz boot=live union=overlay username=user config components quiet noswap noeject toram=filesystem.squashfs ip=  nosplash findiso=$isofile
    	initrd (loop)/live/initrd.img
    }

#### Kali Linux

- Initramfs framework: initramfs-tools (cmdline: RFD)
- Live framework: Debian Live (cmdline: [21])
- Init system: sysvinit (cmdline: RFD)

    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

- Initramfs framework: RFD
- Live framework or installation program: RFD
- Init system: RFD

    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

- Initramfs framework: RFD
- Live framework or installation program: Kiwi? RFD
- Init system: RFD

    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
    }

##### Desktop Live medium

- Initramfs framework: RFD
- Live framework or installation program: Kiwi? RFD
- Init system: RFD

    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
    }

#### Parabola GNU/Linux-libre

Tip: If you want to boot into a 32-bit system, replace `x86_64` with `i686`.

    menuentry '[loopback]parabola-2015.07.01-dual.iso' {
    	set isofile='/boot/iso/parabola-2015.07.01-dual.iso'
    	loopback loop $isofile
    	linux (loop)/parabola/boot/x86_64/vmlinuz parabolaisolabel=PARA_201507 img_dev=$imgdevpath img_loop=$isofile earlymodules=loop
    	initrd (loop)/parabola/boot/x86_64/parabolaiso.img
    }

Tip: The label string after `parabolaisolabel=` needs to be edited when a newer release is used.

#### Sabayon

- Initramfs framework: genkernel? RFD
- Live framework or installation program: RFD
- Init system: openrc? RFD

    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

- Initramfs framework: RFD
- Live framework or installation program: RFD
- Init system: RFD

    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

- Initramfs framework: RFD
- Live framework or installation program: RFD
- Init system: RFD

Note: Replace `64` with `32` if you want to boot into a 32-bit system.

    menuentry '[loopback]systemrescuecd-x86-4.5.2' {
    	set isofile='/boot/iso/systemrescuecd-x86-4.5.2.iso'
    	loopback loop $isofile
    	linux (loop)/isolinux/rescue64 isoloop=$isofile
    	initrd (loop)/isolinux/initram.igz
    }

#### Ubuntu

- Initramfs framework: RFD
- Live framework or installation program: RFD
- Init system: upstart (cmdline: RFD)

    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

- Initramfs framework: RFD
- Live framework: RFD
- Init system: RFD

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

- Initramfs framework: RFD
- Live framework: RFD
- Init system: RFD

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.[22]

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

## See also

- GRUB:
  - https://help.ubuntu.com/community/Grub2/ISOBoot/Examples
  - https://help.ubuntu.com/community/Grub2/ISOBoot
- Syslinux:
  - Boot an ISO image

Category:

- Boot process