Difference between revisions of "USB flash installation media"

Revision as of 11:25, 29 November 2012

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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

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

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 /media/somefolder/arch/boot/syslinux    #The USB drive's mount point. Do not skip this step.
# 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_2012XX 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_2012.*|device=/dev/disk/by-uuid/$(lsblk -no 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

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

Image Writer for Windows

Download the program from http://launchpad.net/win32-image-writer and run it. 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

Linux Live 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. Visit home page for more info.

The Universal USB Installer

Universal USB Installer is a Live Linux USB Creator that allows you to choose from a selection of Linux Distributions to put on your USB Flash Drive.

UNetbootin

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. For example, my output looks like this:

C:\>flashnul -p

Avaible physical drives:
Avaible logical disks:
C:\
D:\
E:\

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

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:

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]:

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

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 smaller download. Use it as shown in instructions for Cygwin above.

Boot the entire ISO from RAM

This method uses Syslinux and MEMDISK to load the entire ISO image in RAM, so make sure you have enough RAM to hold it. Once it's done loading and you see the graphical menu you can simply remove the USB stick and maybe even use it on a different machine to start the process all over again. It also allows booting and installing Arch from (and to) the same USB stick.

1. Format the USB stick as FAT32 and create the following folders:

X:\Boot
X:\Boot\ISOs
X:\Boot\Settings

2. Copy the ISO you'd like to boot to the "ISOs" folder (e.g. archlinux-2012.08.04-dual.iso), and extract from the latest release (e.g. syslinux-4.05.zip):

• ./win32/syslinux.exe to the desktop, or wherever you want.

• ./memdisk/memdisk to the "Settings" folder.

And while you're in this folder, create a syslinux.cfg file:

X:\Boot\Settings\syslinux.cfg

DEFAULT arch_iso

LABEL arch_iso
        MENU LABEL Arch Setup
        LINUX memdisk
        INITRD /Boot/ISOs/archlinux-2012.11.01-dual.iso
        APPEND iso

3. 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:

Done.

See Also

• Gentoo liveusb document