USB flash installation media

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Revision as of 10:53, 10 February 2009 by Seal (talk | contribs) (added a Mac way)
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The New and Improved Way, on Linux

Beginning from release 2008.06, USB images are provided. Download them from your local mirror (they are the .img files). To install, use the following command:

dd if=image.img of=/dev/sd[x]

where image.img is the path to the img file and /dev/sd[x] is your USB device. Make sure to use /dev/sdx and not /dev/sdx1.

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.

The New and Improved Way, on Mac OS X

To be able to use dd on your usb device on a Mac you have to do some special manoveurs. 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. 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.

The New and Improved Way, 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 [sic] physical drives:
0       size = 200048565760 (186 Gb)
1       size = 400088457216 (372 Gb)
2       size = 400088457216 (372 Gb)
3       size = 4060086272 (3872 Mb)

In my case, with a 4 GB USB drive, it is device index 3.

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 3 -L path/to/arch/usb.img

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, unplugging and re-attaching the drive worked for me.

Note! I had to do "C:\flashnul\flashnul.exe H: -L c:\archlinux-2008.06-core-i686.img" for it to work. I kept getting access denied if i just used the number. -gejr

The Cygwin Way

Make sure your cygwin installation contains the dd package.

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.img of=\\.\[x]:

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

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.

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


If you happen to run into "Cluster sizes larger than 16K not supported" error when running syslinux - don't panic, that just means you need to install more recent version of syslinux.

(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.