I have a copy of the Slackware 64 bit dvd installation iso. I've burned this image to a dvd and used it to properly install the distro. I wanted to try also having this image available on a usb flash drive. I divided a 32 GB drive into two partitions: 1, about 22 GB for data; and 2, about 10 GB for messing around with installers (set as bootable). I dd'd the contents of the installation iso to the bootable partition on the flash drive. However, when I tried booting from the usb installer, I was greeted with a message about not being able to find an operating system.

I've previously installed Slackware to a bootable partition on a flash drive and had it properly boot on different machines. This time around, I'd like to have the installer rather than an installed system though.

What am I doing wrong?

  • not 100% but I think bootable ISO's are actually structurally different than bootable partitions (IIRC with isos there's a catalog of files that exist on the disc in the metadata, and it's just that one is listed as being the boot loader instead of the bootloader occupying a specific part of the volume). Have you looked into unetbootin?
    – Bratchley
    Jun 14, 2013 at 3:55
  • more information from tldp Also it looks like this is probably what I was thinking of, in which case el torito boot loaders and regular boot loaders look very different.
    – Bratchley
    Jun 14, 2013 at 4:02
  • Is that -current or the latest release version (14.0)? PV has made a few changes back and forth about the install media since the last release -- check the changelog around March 18-20. Jun 14, 2013 at 4:27

2 Answers 2


It's not Slackware expierence based answer, but it seems that problem is, that iso isn't supposed to be dd'd into flash drive. Probably bootloader is not supposed to load from other source than CD.

Instead you should copy the iso to usb and have bootloader that can handle iso. SysLinux bootloader MEMDISK tool is supposed to handle such use cases: http://www.syslinux.org/wiki/index.php/MEMDISK#ISO_images .

Alternatelly if you still want to load extracted disk image, try installing a bootloader (Syslinux, probably grub2 would work too) into flash drive and link boot menu entry manually to kernel and initrd.


Details depends on the ISO, how it's been designed, and your BIOS configuration.

For BIOS in LEGACY mode:

An ISO can never be stored inside a partition. An ISO is a full disk image. Not a partition image.

In the best case, you can write the full image on a raw disk, like a USB memory stick. But note that the boot sequence for a classic disk and a CD is not similar at all, so, when many ISO images are now designed to be stored on USB stick, it have not always been the case, and may not work for all ISO.

ISO that are designed to be written on USB sticks may work on hard drives as well, but, not always.

You can NEVER re-read a CD/DVD after burning it, to directly create a USB stick. You may think it will works, but in practice, it does not.

In the best case, you must paste the ISO in the USB-memory or HDD first, then, you can edit partition table to create more partitions in the end of the storage media; this is likely to work. But the later partitions won't be bootable.

Never forget that ... before your first partition, there is the MBR !!! And then, one BR per partition (with BIOS partitioning). That's why just pasting the partitions can't work; you also need to copy the MBR, and, to have MBR work, each partition needs to be at the expected address.

For BIOS in UEFI mode:

I believe it's possible to split the partitions of an ISO, and store them on a USB stick or a hard drive, and make them share the disk with other partitions for misc uses, but I don't know how to do it yet.

You also can paste the ISO on the media, and add new partitions as long as there remains free space.

  • This answer is incorrect in several places. You can write an ISO into a partition, I've done so several times. You can "re-read a CD/DVD after burning it", again, I've done so several times. A typical ISO (such as the type you download to install Linux) doesn't have a partition table, since it's just a container for an ISO-9660 file system, thus you can't "edit the file system" after writing the ISO to a flash drive. Nov 15, 2021 at 1:28

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