Difference between revisions of "USB flash installation media"

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where sd[x] is your USB drive's device node (the drive's itself, not the first partition's).
where sd[x] is your USB drive's device node (the drive's itself, not the first partition's).
{{Warning|If you choose the wrong device node here, you might destroy data, so better be sure.}}
{{Warning|If you choose the wrong device node here, you might destroy data, so be sure.}}
The partition table should look similar to this one:
The partition table should look similar to this one:

Revision as of 18:06, 22 August 2011

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This page discusses how to put Arch installation media onto a USB key (or "flash drive"). The result will be a LiveCD-like system that will discard all changes when it is shut down. Consider whether you are instead interested in Installing Arch Linux on a USB key.

On GNU/Linux

Arch USB images

Overwrite the USB drive

Beginning from release 2010.05, all iso files can be directly written to usb media. Download them from your local mirror. To install, first ensure the USB device is unmounted and then issue the following command:

$ dd if=archlinux.iso of=/dev/sd[x] 

where archlinux.iso is the path to the iso file and /dev/sd[x] is your USB device.

Note: You can also add bs=4M to speed up the dd process..
Warning: This will irrevocably destroy all data on /dev/sdx.
Warning: Make sure to use /dev/sdx and NOT /dev/sdx1. This is a very common error!

Without overwriting the USB drive

With release 2011.08.19 or later, you can install the Arch image to USB without overwriting its contents. This is slightly more complicated than copying the image directly, but keeps the drive usable for data storage. Before you begin, make sure that your USB device is formatted as either FAT32, ext2/3/4 or btrfs (for interoperability with other operating systems, you probably want to use FAT32). Also make sure you have syslinux 4.04 installed (older or newer syslinux 4 versions may work, syslinux 3.XX will not work).

First, download and mount the ISO image:

$ mount -o loop /path/to/image/archlinux-XXX.iso /path/to/iso/

Second, mount the USB drive and copy the contents of the /arch folder to its main directory:

$ cp -r /path/to/iso/arch/ /path/to/usb/

The image also contains a /syslinux folder, but you don't need it.

Third, install syslinux to the USB drive:

$ extlinux --install /path/to/usb/arch/boot/syslinux/

You need to adjust the boot configuration files in order for your system to boot. In /path/to/usb/arch/boot/syslinux/*.cfg, replace



archisolabel=<your USB drive label>

In the dual images, this occurs in two places, in the i686 and x86_64 images only once. If your USB drive doesn't have a label, then set one.

If your USB drive has a partition table (most of them do), then you need to install an MBR and make the first partition active:

$ dd bs=440 conv=notrunc count=1 if=/usr/lib/syslinux/mbr.bin of=/dev/sd[x]

where sd[x] is your USB drive's device node (the drive's itself, not the first partition's).

Warning: If you choose the wrong device node here, you might destroy data, so be sure.

The partition table should look similar to this one:

$ LANG= fdisk -l /dev/sdx
   Device Boot      Start         End      Blocks   Id  System
/dev/sdx1   *        2048    15663103     7830528    b  W95 FAT32

As you can see, the first partition (sdx1) has the bootable flag set.

Your USB drive is now bootable.

Note: This method will also work on Windows if you download the latest syslinux version for Windows. The commands will of course be different. Please refer to the syslinux documentation.


Another way to make a USB drive bootable, is by using UNetBootin. This application can download most distributions for you and write them to your flash drive. UNetbootin can download the latest Arch core or netinstall iso for you, or you can supply a manually downloaded one.

It might happen that UNetBootin fails to start showing the following error.

GLib-GIO:ERROR:gdbusconnection.c:2270:initable_init: assertion failed: (connection->initialization_error == NULL)

If this happens try to start it with the following command as normal user.

# su -c "dbus-launch --exit-with-session unetbootin"

If using a version of UNetbootin older than 549, then after it finishes, you will have to adjust syslinux.cfg on the root of your flash drive before rebooting. Correct the "archisolabel=" parameter to reflect the label of the USB drive you used, i.e.:

append initrd=/ubninit archisolabel=<label> tmpfs_size=75% locale=en_US.UTF-8


A third method is to follow the instructions about Booting multiple LiveCD's from a single USB stick. In a nutshell, you create 2 partitions on your USB drive, copy the Gujin boot loader image to the first partition, and copy Arch's ISO to the second.

On Mac OS X

To be able to use dd on your usb device on a Mac you have to do some special maneuvers. First of all insert your usb device, OS X will automount it, and run

diskutil list

in Terminal.app. Figure out what your usb device is called - mine was called /dev/disk1. (Just use the `mount` command or `sudo dmesg | tail`.) Now you run

diskutil unmountDisk /dev/disk1

to unmount the partitions on the device (i.e., /dev/disk1s1) while keeping the device proper (i.e., /dev/disk1). Now we can continue in accordance with the Linux instructions above (but use bs=8192 if you are using the OS X dd, the number comes from 1024*8).

 dd if=image.iso of=/dev/disk1 bs=8192
 20480+0 records in
 20480+0 records out
 167772160 bytes transferred in 220.016918 secs (762542 bytes/sec)

it is probably a good idea to eject your drive before physical removal at this point.

 diskutil eject /dev/disk1

On Windows

To write the USB image on Windows, you will need Image Writer for Windows, Linux Live USB Creator, Universal USB Installer, flashnul (English version of the page), Cygwin, or UNetBootin.

Image Writer for Windows

Image Writer is the only native Windows image writer (except Cygwin) that writes the whole image without any changes (like dd) - other writers unpack the image and then copy all the files to a FAT filesystem.

Download win32 disk imager from http://launchpad.net/win32-image-writer. Run the program. Select the arch image-file and usb stick. The Win32 Disk Imager's file browser assumes image files end with .img, so if the image-file you have selected ends with .iso, you will have to type its name in manually; this difference in suffixes is simply cosmetic however, the image will be written fine regardless. Click on the write button. Now you should be able to boot from the usb stick and install Arch Linux from it.

Linux Live USB Creator

LiLi USB Creator can be used to create a bootable USB key for Arch either using a manually downloaded iso or automatically downloading the iso itself. It also supports automatic installation of VirtualBox on the USB key which can be used to boot Arch inside Windows.

The steps involved are well described by LiLi itself but can be summarized to: download & install LiLi, download Arch iso, insert USB key, start LiLi & choose drive (1), source (2), options (4) and create (5).

I have tested all features except the automatic download of iso, and all works and are quite fast.

The Universal USB Installer

I had problems booting from a USB key created with flashnul under Windows or dd under Linux. I gave a try to the "Universal USB Installer" and it created the bootable USB key which worked fine.

The Flashnul Way

From a command prompt, invoke flashnul with -p, and determine which device index is your USB drive. For example, my output looks like this:

C:\>flashnul -p

Avaible physical drives:
Avaible logical disks:

In my case, it is drive E:

When you have determined which device is the correct one, you can write the image to your drive, by invoking flashnul with the device index, -L, and the path to your image. In my case, it would be

C:\>flashnul E: -L path\to\arch.iso

As long as you are really sure you want to write the data, type yes, then wait a bit for it to write. If you get an access denied error, close any Explorer windows you have open.

If under Vista or Win7, you should open the console as administrator, or else flashnul will fail to open the stick as a block device and will only be able to write via the drive handle windows provides

Note: Confirmed that you need to use drive letter as opposed to number. flashnul 1rc1, Windows 7 x64. -bgalakazam

The Cygwin Way

Make sure your cygwin installation contains the dd package. Or if you do not want to install Cygwin, you can simply download dd for windows from http://www.chrysocome.net/dd.

Place your image file in your home directory, in my case it is:


Run cygwin as administrator (required for cygwin to access hardware). To write to your USB drive use the following command:

dd if=image.iso of=\\.\[x]:

where image.iso is the path to the iso-image file within the cygwin directory and \\.\[x]: is your USB device where x is the windows designated letter, in my case "\\.\d:".

On cygwin 6.0 find out the correct partition with

cat /proc/partitions

and write the ISO image with the information from the output. Example:

dd if=image.iso of=/dev/sdb
Warning: This will irrevocably delete all files on your USB stick, so make sure you do not have any important files on the stick before doing this.


Another way to make a USB drive bootable, is by using UNetBootin (see above)

Old Method from ISO, deprecated

  • Prepare USB stick:

The arch-ftp.img is about 150 MB, so it should fit on a 256 MB USB stick. The arch-core.img is ~300 MB and should fit on a 512 MB stick.

Partition the USB stick.

Create one partition with FAT16 type, make it bootable. Remember its name, such as /dev/sd[x]1.

cfdisk /dev/sd[x]

Make a FAT16 filesystem (you need dosfstools)

mkdosfs /dev/sd[x]1

Get the arch-base install ISO from http://archlinux.org/

wget http://www.archlinux.org/iso/2010.05/archlinux-2010.05-netinstall-dual.iso.torrent
pacman -Qq rtorrent || pacman -S rtorrent
rtorrent archlinux-2010.05-netinstall-dual.iso.torrent

Mount the iso to an temporary directory

mkdir -p /mnt/archcd
mount -o loop /Path/to/iso /mnt/archcd

Mount the USB Stick

mkdir -p /mnt/usb/
mount /dev/sd[x]1 /mnt/usb/

Copy the .iso to the USB Stick

cp -ra /mnt/archcd/* /mnt/usb/

Copy the boot data

cd /mnt/usb/isolinux/
cp vmlinuz /mnt/usb/
cp initrd.img /mnt/usb/
cp boot.* /mnt/usb/
cp isolinux.cfg /mnt/usb/syslinux.cfg
Note: For release 2010.05, replace those command lines by the following
cd /mnt/usb/
cp boot/isolinux/isolinux.cfg ./syslinux.cfg
sed /IPAPPEND/d syslinux.cfg
cp /usr/lib/syslinux/vesamenu.c32 ./
cp /usr/lib/syslinux/chain.c32 ./
cp /usr/lib/syslinux/reboot.c32 ./

Install MBR and syslinux(1)

lilo -M /dev/sd[x] mbr
syslinux -s /dev/sd[x]1
Note: For release 2010.05, replace those command lines by the following
syslinux --install /dev/sd[x]1
cat /usr/lib/syslinux/mbr.bin > /dev/sd[x]

After booting from the USB stick:

Start the installation by logging in as root and invoke the command "/arch/setup".

The installer should mount the source media automatically. If it fails you can manually mount the source media on the stick to the /src directory with the following command:

mount /dev/sd[x] /src

Notes and Troubleshooting:

(1) Using lilo is not really needed because syslinux does the "floppy" loading stuff. But if you get some error like "Can't load operating system" you have to perform the lilo command.

(2) If you get "Cluster sizes larger than 16K not supported" error when booting this means you need to install more recent version of syslinux.

(3) Space not used on the USB stick can still be used for storing files... Use a utility like gparted and add a partition to the unused space.