How To Install Unbuntu From USB Device

目录

Ubuntu is distributed over the Internet as two types of files: CD image files, called ISOs, and flash image files, called IMGs. [Warning: This applies just to Ubuntu 9.04. Ubuntu is NO LONGER distributed in IMG format, except for some machines ]. To install Ubuntu from flash media, you first need to write the downloaded IMG image to your flash device. This requires a working flash writer (e.g. USB stick, SD reader, etc.), and flash media with sufficient capacity for the install (1 GB or larger is recommended) formatted in FAT32. Commonly, a single USB stick is used to fulfill both requirements.

Warning: This will destroy all data on the USB device. Please backup all data to other media before proceeding.

Be sure to verify that your computer supports booting from the device you have selected for installation. Many computers can boot from a USB drive, and some from other sources. Check the documentation on your specific model of computer for the procedure to boot from the selected device.

If you have downloaded an ISO image, please refer to .

The page has links to the IMG and ISO image files, as well as other methods of .

MD5 Sums

Before writing your flash, it is highly recommended that you verify the md5 sum (hash) of the .img file. For instructions, please see . For the current list of Official Ubuntu MD5 hashes, see the MD5SUMS file for the release you're using under (and optionally the signatures in the MD5SUMS.gpg file), or see . This ensures that the file was not damaged during the download process and is 100% intact.

Windows

Graphical Interface

1. Download the desired .img file

2. Download Disk Imager from https://launchpad.net/win32-image-writer/+download

3. Insert your flash media
4. Note the drive letter assigned to your flash media
5. Start Disk Imager
6. Select the downloaded file and target device, and click "Write"
7. Remove your flash media when the operation is complete

Command Line Interface

1. Download the desired .img file

2. Download flashnul from

3. Attach your USB drive

4. Run flashnul -p

5. Note the physical device number for the USB drive

6. Run flashnul  -L \path\to\downloaded.img

7. Answer "yes" if the selected destination device is correct
8. Remove your USB drive when the command completes

Ubuntu

Graphical Interface

1. Download the desired .img file
2. Install the usb-imagewriter package

   • If your release does not include this, download it from

   • If imagewriter fails to launch, you may need to install python glade2 support. Install the python-glade2 package or Run sudo apt-get install python-glade2

   • If your release does not include it and you are running 9.04 Jaunty Jackalope then run this command from the console:

     • sudo apt-get install usb-imagewriter

3. Open Applications -> Accessories -> Image Writer

   • KDE users will find this in Applications -> Utilities -> Image Writer

   • from the command line, from the console:

     • sudo imagewriter

   • on some usb-imagewriter versions (console command: imagewriter) the application fails to write if the image path contains blank spaces, exiting with ": list index out of range".

4. Insert your flash media
5. Select the downloaded file and flash device, and click "Write to Device"
6. Remove your device when the operation is complete

Command Line Interface

Be very careful about which /dev device you write to. If your machine is booted up off of disk /dev/sda, and your usb stick is on /dev/sdc, and you accidentally write to /dev/sda instead of /dev/sdc, your filesystem will be irreparably damaged and you will lose all of your files.

1. Download the desired .img file
2. Open a terminal and insert your flash media

3. Look at the output of sudo dmesg | tail -20 to determine the device node assigned to your flash media (ignore the device number; e.g. /dev/sdc, not sdc1)

   • Example output of dmesg, where the device node is 'sdc':

   • [ 5046.396364] usb-storage: device scan complete

   • [ 5046.397075] scsi 10:0:0:0: Direct-Access USB Flash Memory 1.00 PQ: 0 ANSI: 0 CCS

   • [ 5047.068761] sd 10:0:0:0: [sdc] Mode Sense: 23 00 00 00

   • [ 5047.068769] sd 10:0:0:0: [sdc] Assuming drive cache: write through

   • [ 5047.075021]  sdc: sdc1

   • [ 5047.076459] sd 10:0:0:0: [sdc] Attached SCSI removable disk

4. Run sudo umount /dev/devicenode

5. Run sudo dd if=/path/to/downloaded.img of=/dev/devicenode bs=1M

6. Remove your flash media when the command completes (you may need to wait a few extra seconds for it to finish)

Mac OS X

Command Line Interface

1. Download the desired .img file
2. Open a Terminal (in /Applications/Utilities/)

3. Run diskutil list to get the current list of devices

4. Insert your flash media

5. Run diskutil list again and determine the device node assigned to your flash media (e.g. /dev/disk2)

6. Run diskutil unmountDisk /dev/diskN (replace N with the disk number from the last command; in the previous example, N would be 2)

7. Execute sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m (replace /path/to/downloaded.img with the path where the image file is located; for example, ./ubuntu.img, /dev/rdiskN is faster than /dev/diskN). If you see the error dd: Invalid number `1m', you are using GNU dd. Use the same command but replace bs=1m with bs=1M.

8. Run diskutil eject /dev/diskN and remove your flash media when the command completes

External USB disc drives

IMG files can also be written to external USB hard discs and installed by having the computer boot from the external USB disc drive.