USB flash installation media

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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's shut down. Consider whether you're instead interested in Installing Arch Linux on a USB key.

On GNU/Linux

Arch USB images

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=image.iso of=/dev/sd[x]

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

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!

brain0 made a nice post on his blog on Arch Linux USB Install and Rescue Media where he explains how to have several partitions on the USB stick with some accessible from windows.


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 UNetBootin is using a heavily outdated Arch ISO version, so you must supply a manually downloaded iso file.

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"

After Unetbootin finishes, you 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 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're 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)

On Windows

To write the USB image on Windows, you will need flashnul (English version of the page) or Cygwin.

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 don't want to install Cygwin, you can simply download dd for windows from

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

Note: This will irrevocably delete all files on your USB stick, so make sure you don't have any important files on the stick before doing this.

win32 disk imager

Download win32 disk imager from 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've 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.


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.

1. 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]

2. Make a FAT16 filesystem (you need dosfstools)

mkdosfs /dev/sd[x]1

3. Get the arch-base install ISO from

4. Mount the iso to an temporary directory

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

5. Mount the USB Stick

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

6. Copy the .iso to the USB Stick

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

7. 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

8. Install MBR and syslinux(1)

lilo -M /dev/sd[x] mbr
syslinux -s /dev/sd[x]1

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.