Difference between revisions of "USB flash installation media"

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This page discusses various methods on how to write an Arch Linux release to a USB drive (also referred to as "flash drive", "USB stick", "USB key", etc). The result will be a LiveCD-like system ("LiveUSB", if you will) that, because of the nature of SquashFS, will discard all changes once the computer shuts down.

If you would like to run a full install of Arch Linux from a USB drive (i.e. with persistent settings), see Installing Arch Linux on a USB key.

On GNU/Linux

Overwrite the USB drive

# dd bs=4M if=/path/to/archlinux.iso of=/dev/sdx && sync

How to restore the USB drive

Because the ISO image is a hybrid which can either be burned to a disc or directly written to a USB drive, it doesn't include a standard partition table.

After you install Arch Linux and you're done with the USB drive, you should zero out its first 512 bytes (meaning the boot code from the MBR and the non-standard partition table) if you want to restore it to full capacity:

# dd count=1 bs=512 if=/dev/zero of=/dev/sdx && sync

Then create a new partition table (e.g. "msdos") and filesystem (e.g. EXT4, FAT32) using gparted, or from a terminal:

• For EXT2/3/4 (adjust accordingly), it would be:

# cfdisk /dev/sdx
# mkfs.ext4 /dev/sdx1
# e2label /dev/sdx1 USB_STICK

• For FAT32, install the dosfstools package and run:

# cfdisk /dev/sdx
# mkfs.vfat -F32 /dev/sdx1
# dosfslabel /dev/sdx1 USB_STICK

Without overwriting the USB drive

This method is slightly more complicated than writing the image directly with dd, but it does keep 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 UEFI boot and/or interoperability with other operating systems you should use FAT32. Also, make sure that you have the syslinux package (version 4.04 or newer) installed.

1. Extract the arch folder from the ISO to the USB drive. For UEFI motherboards follow these instructions.

2. Install the Syslinux bootloader:

$ cd /path/to/folder/arch/boot/syslinux #Where path/to/folder is the USB drive's mount point
# extlinux --install .                       #Type it exactly as you see it, including the dot (.)
# dd bs=440 conv=notrunc count=1 if=/usr/lib/syslinux/mbr.bin of=/dev/sdx
# parted /dev/sdx toggle 1 boot

3. Adjust the configuration files:

Here's how you can replace the archisolabel=ARCH_2013XX part with your equivalent of archisodevice=/dev/disk/by-uuid/47FA-4071 for both config files at the same time, using a single command:

$ sed -i "s|label=ARCH_.*|device=/dev/disk/by-uuid/$(blkid -o value -s UUID /dev/sdx1)|" archiso_sys{32,64}.cfg

If the syslinux package on your distribution is older than version 4.06, as a workaround for FAT32 filesystems (unnecessary for EXT4), the APPEND line from syslinux.cfg should also be replaced:

$ sed -i "s|../../|/arch|" syslinux.cfg

Using UNetbootin

UNetbootin can be used on any Linux distribution or Windows to copy your iso to a USB device. However, Unetbootin overwrites syslinux.cfg, so it creates a USB device that does not boot properly. For this reason, Unetbootin is not recommended -- please use dd or one of the other methods discussed in this topic.

Edit syslinux.cfg:

sysconfig.cfg

default menu.c32
prompt 0
menu title Archlinux Installer
timeout 100

label unetbootindefault
menu label Archlinux_x86_64
kernel /arch/boot/x86_64/vmlinuz
append initrd=/arch/boot/x86_64/archiso.img archisodevice=/dev/sdx1 ../../

label ubnentry0
menu label Archlinux_i686
kernel /arch/boot/i686/vmlinuz
append initrd=/arch/boot/i686/archiso.img archisodevice=/dev/sdx1 ../../

In /dev/sdx1 you must replace x with the first free letter after the last letter in use on the system where you are installing Arch Linux (e.g. if you have two hard drives, use c.). You can make this change during the first phase of boot by pressing Tab when the menu is shown.

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 in Terminal.app run:

$ diskutil list

Figure out what your USB device is called with mount or sudo dmesg | tail (e.g. /dev/disk1) and unmount the partitions on the device (i.e., /dev/disk1s1) while keeping the device proper (i.e., /dev/disk1):

$ diskutil unmountDisk /dev/disk1

Now we can continue in accordance with the 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

Win32 Disk Imager

First, download the program from here. Next, extract the archive and run the executable. Now, select the Arch Linux ISO under the Image File section and the USB flash device letter (for example, [D:\]) under the Device section. Finally, click Write when ready.

USBWriter for Windows

Download the program from http://sourceforge.net/projects/usbwriter/ and run it. Select the arch image file, the target USB stick, and click on the write button. Now you should be able to boot from the usb stick and install Arch Linux from it.

The Flashnul Way

flashnul is an utility to verify the functionality and maintenance of Flash-Memory (USB-Flash, IDE-Flash, SecureDigital, MMC, MemoryStick, SmartMedia, XD, CompactFlash etc).

From a command prompt, invoke flashnul with -p, and determine which device index is your USB drive, e.g.:

C:\>flashnul -p

Avaible physical drives:
Avaible logical disks:
C:\
D:\
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, e.g:

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

The Cygwin Way

Make sure your Cygwin installation contains the dd package.

Place your image file in your home directory:

C:\cygwin\home\John\

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]: bs=4M

where image.iso is the path to the iso image file within the cygwin directory and \\.\[x]: is your USB flash drive where x is the windows designated letter, e.g. \\.\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 bs=4M

dd for Windows

A GPL licensed dd version for Windows is available at http://www.chrysocome.net/dd. The advantage of this over Cygwin is a smaller download. Use it as shown in instructions for Cygwin above.

To begin, download the latest version of dd for Windows. Once downloaded, extract the archive's contents into Downloads or elsewhere.

Now, launch your command prompt as an administrator. Next, change directory (cd) into the Downloads directory.

If your Arch Linux ISO is elsewhere you may need to state the full path, for convenience you may wish to put the Arch Linux ISO into the same folder as the dd executable. The basic format of the command will look like this.

dd if=archlinux-2013-XX-xx-dual.iso of=\\.\x: bs=4m

Simply replace the various null spots (indicated by an "x") with the correct date and correct drive letter.

Here is a complete example.

dd if=ISOs\archlinux-2013.08.01-dual.iso of=\\.\d: bs=4M

Loading the installation media from RAM

This method uses Syslinux and a Ramdisk (MEMDISK) to load the entire Arch Linux ISO image into RAM. Since this will be running entirely from system memory, you will need to make sure the system you will be installing this on has an adequate amount. A minimum amount of RAM between 500 MB and 1 GB should suffice for a MEMDISK based, Arch Linux install.

For more information on Arch Linux system requirements as well as those for MEMDISK see the Beginners' Guide and here.

Preparing the USB flash drive

Begin by formatting the USB flash drive as FAT32. Then create the following folders on the newly formatted drive.

• Boot
  • Boot/ISOs
  • Boot/Settings

Copy the needed files to the USB flash drive

Next copy the ISO that you would like to boot to the Boot/ISOs folder. After that, extract from the following files from the latest release of syslinux from here and copy them into the following folders.

• ./win32/syslinux.exe to the Desktop or Downloads folder on your system.
• ./memdisk/memdisk to the Settings folder on your USB flash drive.

Create the configuration file

After copying the needed files, navigate to the USB flash drive, /boot/Settings and create a syslinux.cfg file.

/Boot/Settings/syslinux.cfg

DEFAULT arch_iso

LABEL arch_iso
        MENU LABEL Arch Setup
        LINUX memdisk
        INITRD /Boot/ISOs/archlinux-2013.08.01-dual.iso
        APPEND iso

For more information on Syslinux see the Arch Wiki article.

Final steps

Finally, create a *.bat file where syslinux.exe is located and run it ("Run as administrator" if you're on Vista or Windows 7):

C:\Documents and Settings\username\Desktop\install.bat

@echo off
syslinux.exe -m -a -d /Boot/Settings X:

Add to a MULTIBOOT Live USB

The Windows tool YUMI MultiBoot Live USB Creator can be used to quickly create a Live USB media with multiple Installers of many Linux distros. Once created, Installers can be added or removed without reformatting the USB drive.

Troubleshooting

See Also

• Gentoo liveusb document