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Creating a bootable USB drive from an ISO image
What's an ISO?
Why would you want to write an ISO to a USB drive?
Typically one of two reasons:
- Compatibility: You want to boot the ISO on a physical computer that doesn't have a CD drive.
Originally ISO files were intended to be burned to physical CDROM discs. Unfortunately while most virtualization software (e.g., KVM, VMWare, VirtualBox) has support for inserting ISO images into "virtual" CD readers, physical CD readers are a dying breed.
- Convenience: USB flash drives are smaller, faster, rewriteable and more robust than a clumsy, flat, scratchable CD.
Using isohybrid + dd
The isohybrid tool in the syslinux package will convert ISO images into a USB flash drive compatible format:
# apt-get install syslinux # isohybrid path/to/image.iso
Use lsblk to identify the device path (e.g., /dev/sdX) of your USB drive:
# lsblk sde 8:64 1 7.4G 0 disk └─sde1 8:65 1 7.4G 0 part /media/usbdrive
If it's been automounted, as is the case above, unmount it first:
# umount /media/usbdrive
Use dd to write the ISO image to the disk path. That's /dev/sde NOT /dev/sde1:
dd if=path/to/image.iso of=/dev/sde
- Root access is required: You will need to perform the above commands as root. On Ubuntu prepend the commands with sudo (e.g., sudo apt-get install syslinux)
- dd will completely overwrite your USB drive: Any data on it will be lost so if you use this method you'll want to use it with a dedicated USB device.
- dd needs to write to the disk path, not the partition path: in the above example /dev/sde is the disk path device, /dev/sde1 is the partition path (e.g., sde1 is the first partition on sde). You need to write to the disk path because isohybrid prepends a partition structure to the ISO.
How isohybrid works
Starting in version 3.72, ISOLINUX supports a "hybrid mode" which can be booted from either CD-ROM or from a device which BIOS considers a hard disk or ZIP disk, e.g. a USB key or similar. These isohybrid images contain in addition to the normal CD-based ISO9660 filesystem, a valid-looking DOS-style partition table. So if you simply "raw" copy an isohybrid processed image to a USB flash drive, the BIOS will boot the image directly.
iso2usb.py helper script
Syntax: iso2usb.py iso_path usb_device
iso2usb: Create a bootable USB flash drive containing ISO image
Arguments:
iso_path Path to ISO (e.g., product.iso)
usb_device USB device path (e.g., /dev/sdc)
Options:
--force Not implemented, interactive confirmation required
# iso2usb.py turnkey-core-13.0-wheezy-amd64.iso /dev/sdc **************************************************************************** iso: turnkey-core-13.0-wheezy-amd64.iso (hybrid: False) usb: disk/by-id/usb-SanDisk_Cruzer_Blade_200601650311ADD19323-0:0 (/dev/sdc) **************************************************************************** Is the above correct? (y/N):
Additionally, iso2usb will check whether the ISO image has been pre-processed with isohybrid, and if not it will process the image before writing it.
Once completed, the USB flash drive should now boot directly, showing exactly the same bootup screen as if you'd written the image directly to a CD.
The old pre-isohybrid version of iso2usb
If for some reason your ISO isn't using ISOLINUX as the bootloader you might want to try the old pre-isohybrid version of the iso2usb.py script which I wrote a few years ago. It extracts the ISO to the USB drive together and then installs syslinux. Recently I tried using it but hit issues related to changes in isolinux, which has since introduced the new isohybrid method.
The future
All future TurnKey ISO's will be pre-processed with isohybrid, making it that little bit more TurnKey for installing ISO's to USB flash disks.
Comments
Nice...I've been looking for a portable apps alternative
Thanks Alon. Much appreciated.
I've been providing clients with a dashboard based on portableapps.com with mixed satisfaction. The portableapps model requires the apps to be stripped down to work in the framework. Getting up-to-date apps and then having no decent support model when the apps don't work is less than ideal.
I like the idea of a mini LXC-based Turnkey linux to deploy dashboards & dev environments to my clients.
Should be good :-)
FYI - Minor typo...your script link label says usb2iso rather than iso2usb.
Cheers,
Tim (Managing Director - OnePressTech)
Glad you find it useful...
Glad you'll find it useful! The idea of using TurnKey LXC with pre-cached images sounds very interesting indeed.
I personally use it as I've swapped out my laptops CD drive for a second harddrive to compliment my SSD, and I thought it would make sense to share what I've done, as well as pre-process all future ISO's for hybrid mode...
Great post Alan!
Great post Alan! Flash drives aren't just faster and re-usable (compared to CD drives) they’re also smaller. Occupy less space. One can also send the data on flash drives with the busines logo etc on it.
Interesting, but I've gotten by with only dd
This is interesting because I've always gotten away with dd'ing the ISO to the USB drive directly, without converting the ISO first.
Although, could it simply be that Ubuntu, Debian, and Mint release their ISOs as hybrids to begin with?
They must be hybrid ISO to start with
AFAIK Ubuntu have been producing hybrid ISOs for quite some time now. I would assume that Mint (as an Ubuntu derivative) has also been doing that. Debian OTOH haven't been doing it quite so long but at least since Wheezy. So I guess you've just been lucky! :)
isohybrid is in the syslinux-utils package starting with jessie
In case this helps anyone, you'll need to install syslinux-utils instead of syslinux starting with Debian jessie (a.ka. "testing" at the time of writing, soon to be stable). See: https://packages.debian.org/search?suite=jessie&arch=any&mode=exactfilename&searchon=contents&keywords=isohybrid
Thanks!
Thank you very much for this very useful guide and for the script as well!
Cheers,
Martin
how to restore USB?
Hi,
I have created a USB bootable as per the above mentioned the method.
But now, the USB disk is not usable for data storage.
How can I make it a FAT32 system again?
Thanks
Format it! :)
wait a sec
After the umount step, I try to use dd like you say and it gives me the error:
dd: opening `/dev/sde': No medium found
The "e" is variable
Did you do the lsblk command to see your devices?
On my computer, it was sdb not sde.
I'm guessing your device is something other than e.
Otherwise, perhaps the udb drive is not being recognized at all.
Still a way to get ISOLINUX working again with TKLDEV Wheezy 64?
trying to build some 64 Bit systems both in Jessie and Wheezy.
Wheezy 64 TKLDEV Fails "can't find ISOLINUX" no matter what. For some reason 386 / 32 Version of Wheezy TKLDEV does not.
Working forward on Jessie but so many other changes in terms of SSL/Apache that wanted to at least get a working system on that level for app tuning.
Seems it would be good that Wheezy TKLDEV works as most people are working with Wheezy still. (Broken record I know... but working forward on Jessie too).
--------
References to IsoLinux
IN COMMON
plans/boot
syslinux-common # Collection of bootloaders (common)
5
isolinux # Collection of bootloaders (ISO 9960 bootloader)
Quite a few in
turnkeylinux/tklpatch
Shell
bin/tklpatch-prepare-cdroot
Showing the top three matches. Last indexed on Jul 19, 2014.
38
[ -d $rootfs ] || fatal "no such directory: $rootfs"
39
40
echo "# preparing cdroot"
41
mkdir -p $cdroot/casper
42
mkdir -p $cdroot/isolinux
43
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if [ ! -f $cdroot/isolinux/isolinux.cfg ]; then
45
cat>$cdroot/isolinux/isolinux.cfg<<'EOF'
46
DEFAULT /casper/vmlinuz boot=casper initrd=/casper/initrd.gz ramdisk_size=1048576 root=/dev/ram rw showmounts debug toram=196 --
Shell
bin/tklpatch-geniso
Showing the top three matches. Last indexed on Jul 19, 2014.
45
genisoimage -o $newimage -r -J -l \
46
-V $TKLPATCH_ISOLABEL \
47
-b isolinux/isolinux.bin \
48
-c isolinux/boot.cat \
Shell
bin/tklpatch-extract-iso
Showing the top two matches. Last indexed on Jul 19, 2014.
47
echo "# extracting root filesystem and isolinux from ISO"
48
mkdir -p $cdroot
49
mkdir -p $name.mount
50
mount -o loop $isofile $name.mount
…
53
unsquashfs -d $rootfs $name.mount/casper/*root.squashfs
54
cp -a $name.mount/isolinux $cdroot/
docs/RelNotes-0.92.txt
Showing the top match. Last indexed on Jul 19, 2014.
11
- if cdroot-dir is not provided, a minimal isolinux.cfg will be created
12
to automatically boot the image
13
14
15
* added support for configuration hooks (advanced usage)
then only One in
TKLDEV (APP)
found: docs/helloworld.rst
66
cp build/root.sandbox/usr/lib/syslinux/isolinux.bin build/cdroot/isolinux
67
cp build/root.sandbox/boot/vmlinuz-3.2.0-4-amd64 build/cdroot/casper/vmlinuz
…
96
root (0)
97
genisoimage -o build/product.iso -r -J -l -V core -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table build/cdroot/
Thanks!
Thank you very much!
Burn ISO Image File to USB Drive
Nice post,thanks for sharing!There also is a post that would show you how to burn an ISO to USB drive or/and copy ISO to USB flash drive for data storage only, rather than creating ISO to bootable USB flash drive.
Doesn't work in all cases
I'm using LMDE Cinnamon Edition and wish to convert the Kaspersky rescue disk (to repair a windows box) from their downloaded .iso to boot the box off a USB flash drive.
following the instruction gives rise to this:
root: isohybrid kav_rescue_10.iso
isohybrid: kav_rescue_10.iso: boot loader does not have an isolinux.bin hybrid signature. Note that isolinux-debug.bin does not support hybrid booting
So it would appear that there are cases that isohybrid can't handle. This is not made clear in the article.
No it doesn't...
Did you try the old version that Alon links to? Liraz quotes it in this post? Perhaps that will work...?
Thanks. Good info, no bullshit.
Man, I've always just played it lazy, and burned my .iso images to a dvd, but a relative's godawful netbook with no optical drive went belly up, and I wound up being unfortunate enough to try to repair it.
I just spent the last hour looking at stackoverflow posts saying things like "reboot into Windows and download this program to write the image", "burn Ubuntu to a dvd, then boot up, then use their 'install-to-usb' utility", or "use UNetbootin" (which never produced a bootable USB stick) and I KNEW it was simpler than all that nonsense.
Thanks. I didn't know about isohybrid, and that was the step I was missing.
kernel error
got this message after running the live cd
early console in setup code
this kernel requires an x86-64 cpu,but only detected an i686 cpu.
unable to boot - pls use a kernel appropriate for your cpu.
where can I get to choose the proper iso's to burn?
thanks
Help
Can u tell me how manualy make some program to boot in usb? because in some case in building linux from the scratch.. we can't use that way to do it
sorry for my english, i'm an indonesian hehe
what about multiple ISOs?
Is there some kind of tree structure iso that will let youchoose between several ISOs on a usb drive? Actually I know of one but sometimes it has not worked when I wanted to, probably from me forgetting exactly the right way to implement its use, called Multisystem. the isohybrid command knowledge above I wonder if that was actually already applied to the multisystem iso, and if I dd it to the usb device it just works, then I drag and drop isos into the right folder and wala, multiple OS's. Will have to try this.
I use cp myself
Thank you!
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