USB Flash Drive Boots ISO Image

Symptom:

You have a bootable CD/DVD or an ISO image of one, but your machine has no optical (CD) drive. How are you going to boot it?

How to fix:

Copy it to a USB flash drive, and boot that.

There are several programs that can make a bootable USB drive out of an ISO image; the one I used was UNetbootin. You can download it from that site, but it's also available on the SuSE Build Service and on similar sites for other distros, simplifying installation.

Here's the procedure:

• Install UNetbootin according to your distro's procedure.

• Download your ISO image (or put the CD in the drive).

• Prepare your USB flash drive.

  • It needs to be at least as big as the ISO image, plus a little overhead.
  • It needs to be partitioned, typically one partition covering the whole disc. Look in your syslog or "ls /dev/sd*", to detect which drive letter you got: in my case /dev/sdd. Then use Gnu parted (see its man page) to print the partitioning and to make the partition if not already there.
  • Make a FAT32 filesystem on it. Here's the command line. The argument of the -n option is the disc label; I need to distinguish the OS version (13.1) and the architecture (x86_64 vs. i586).

    mkfs -t fat -F 32 -n suse-131-64 /dev/sdd1

  • Mount it; unetbootin needs it to be already mounted.

    mount /dev/sdd1 /mnt

• Execute: unetbootin (command line arguments are possible but I didn't use them).

• The initial screen gives you a choice of downloading an ISO image from one of the major distros (not necessarily the latest) or of using your own image. Pick the latter; type ISO (vs. floppy); use the … (browse) button to pick it. In the bottom row, select type USB (vs. hard disc), pick the correct drive, and hit OK.

• It copies files for two or three minutes depending on the size of the ISO image, pausing on Installing Bootloader.

• When it finishes, DON'T Reboot Now, just exit.

• sync; umount /mnt; and remove the USB flash drive.

• Now plug it into the machine that you're installing (or rescuing) Linux on, and boot that one. You may need to hit a special key to get a boot menu that includes the USB flash drive; it's F12 on Dell. Or you may need to monkey with the boot order in setup (F2 on Dell; Delete key on some others).