Boot Grml from usb-stick/firewire-device

Grml officially supports booting from usb-stick with all grml flavours. First of all make sure your system supports booting via usb/firewire. Some hardware claims to be able to boot via usb/firewire but does not really support it the way it should work. :-/

Please consider using grml2usb for installing grml on your usb device! It does all the single steps automatically for you with just one single command line! (See below.)

You have three main options how to install a Grml ISO to your usb device:

  1. install using grml2usb (flexible, easy to use)
  2. install using dd
  3. install using a manual approach

grml2usb will perform all the annoying procedures automatically with one single command line for you (except for the device partitioning of course)! Make sure you have a recent version of the grml2usb Debian package installed. Check out or the grml2usb manpage for details.

Note: starting with grml2usb version 0.9.2 it's not a shellscript anymore, instead grml2usb is completely rewritten from scratch in Python. It provides a much more powerful interface, featuring multi-ISO support, providing support for additional bootoptions, grub as bootmanager and automatic installation of a known-to-work MBR (master boot record).

Install using dd

Starting with release 2009.10 the grml ISOs are capable of being dd-ed to a device. This means that you can install a given grml ISO to your USB device using dd(1) like:

dd if=grml.iso of=/dev/sdX

where /dev/sdX corresponds with your USB device (e.g. /dev/sdb). Please note that executing this command will destroy any existing data on your USB device. This method is not as flexible as using grml2usb (lacks support for multi-ISO, specifying additional default bootoptions,…) but might be useful if grml2usb isn't an option for you.

Note: if you are using Windows you might want to use win32-image-writer (just rename the Grml-ISO to grml*.img) or RawWrite dd.

Manual approach

  • Make sure syslinux and mkfs.vfat are available on your system ('aptitude install syslinux dosfstools')
  • Get the grml iso
  • Mount the iso loopback (e.g. mount -o loop grml_small_0.4.iso /mnt/grml-iso)
  • Make FAT16 filesystem on the usbstick (e.g. mkfs.vfat -F 16 -v /dev/sda1)
  • Create a disklabel (e.g. dosfslabel /dev/sda1 GRML)
  • Mount the usbstick (e.g. mount /dev/sda1 /mnt/external1)
  • Copy everything to the usbstick (e.g. cp -r /mnt/grml-iso/* /mnt/external1).
  • Move all files from /mnt/external1/boot/isolinux/ (mv /mnt/external1/boot/isolinux/* /mnt/external1/) to root of usb-stick
    • recent grml versions (>= grml 2008.11): the files linux26 and initrd.gz must remain in boot/$FLAVOUR (/boot/grml, /boot/grmlmedium,…), but it is necessary to copy both to /mnt/external1, while using syslinux v3.63 (ubuntu 8.10)
    • old grml versions (older than grml 2008.11): move the files linux26 and minirt.gz (for grml 1.1: initrd.gz!) from the directory named like the grml-flavour (/boot/grml, /boot/grmlmedium, /boot/grml64,…) to the root of the usb-stick
  • Umount the usbstick and the grml-iso
  • Run syslinux on the usbstick (e.g. syslinux /dev/sda1)
  • Check if the usbstick has an valid mbr, else dd if=mbr.bin of=/dev/sda (mbr.bin is in the syslinux package, usually installed in /usr/lib/syslinux/mbr.bin)
  • You may need to set the bootable flag using parted (or fdisk)

Building an EFI USB Key on a Mac

  • Plug in a 512MB+ blank USB key
  • Start Disk Utility
    • Select the USB Key
    • Choose the “Partition” tab
      • Select Partition Layout: “1 Partition”
      • Options: tick “GUID Partition Table”
      • For the partition format, choose “MS-DOS (FAT)”
      • Apply
  • Mount the grml64 ISO in Finder (must be 2011.12 or newer)
  • Using Finder, copy all files from the ISO to the USB key partition (should be labeled “UNTITLED 1” by now)
  • Done!

To boot this on a Mac, hold down the Option (alt) key while rebooting and select “EFI Boot” from the Disk Chooser.

(If you have nVidia graphics, you must select “Disable Kernel-Mode-Setting” due to bugs in the drivers.)


  • Try to boot with 'grml noapic noacpi pci=noacpi' - some laptops seem to have problems with ACPI and the usb/firewire-modules.
  • Maybe syslinux was not properly installed on the USB device. Some BIOS/systems require the “safe, slow and stupid” version of syslinux so you have to install syslinux using the -s option ('syslinux -s /dev/…'). Or if you are installing it on a 2 GB USB stick it may complain about blocksizes >512 bytes. Using GRUB instead should solve the problem.
  • The boot menu appears, but when booting grml, it fails with: “Could not find kernel image: /boot/”. Your syslinux version may be too old. This could be solved by upgrading from syslinux-3.31 to version 3.52.
  • If your usbstick is too large for FAT16 you can try using FAT32 (e.g. mkfs.vfat -F 32 -v /dev/sda1 -n grml). Or you repartition it with a smallish first partition. Be aware that Windows XP “sees” only the first partition on an usbstick! So you can try a largeish first partition for windows and a second small one (around 700MB for full grml) right at the end of the stick.

System-specific workarounds

  • On an IBM Thinkpad T60 the initrd.img gets loaded half through, then booting just stops. Upgrade to a newer syslinux package. I got it working with 3.63
  • On an Intel Desktop board with PhoenixBIOS, I needed to set “USB Mass Storage Emulation Type” to “Fixed Disk”, the default of “Auto” resulted in an “Boot Error” message.

Does not boot at all?

Unfortunately, booting from a USB stick is not pretty well supported by all BIOSses. Some BIOSses offer different modes for USB booting. The proper mode to boot a USB stick is “USB-HDD”. If that doesn't work or is not supported by your system, you need to format your USB-Stick as USB-ZIP.

To do this, the syslinux source distribution contains an utility called mkdiskimage, which you can use to re-format your USB stick in USB-ZIP format. This procedure will erase all data on your stick, and leave you with the stick not being used to its full capacity due to rounding requirements:

# mkdiskimage -4 /dev/<your-usb-stick-device> 0 64 32

Then continue installing as usual. Note that this is not going to work for any device larger than 8 GB, since mkdiskimage only supports 1024c 256h 63s. For a more detailed explanation, refer to /usr/share/doc/syslinux-common/usbkey.txt.

Notice: your USB device is accessed after running the BIOS routine and you get “No operating system found”? Make sure the grml-iso is on the first partition of the USB device and that the partition really starts at the first sector of the USB device. Verify this via running 'cfdisk /dev/sda' (adjust /dev/sda to your usb device). If 'cfdisk' doesn't work, use fdisk or [g]parted. Also, make sure that the disk is bootable. There should be a * (star) below column 'boot'.

grml2hd on usb/firewire devices

If you installed grml on an external harddisk (usb/firewire) through grml2hd please make sure the root= option on the kernelcommand line (in lilo/grub) is correct, otherwise booting will fail as the root filesystem can not be found. To work around the issue at all you could use labels/UUIDs as well.

Grml on usb devices and DVDs via WinBuilder

Based on the tool WinBuilder you can build Boot-CDs and USB-Boot-Devices.

Making a bootable grml32/grml64/ubuntu usb-stick

This is surprisingly easy to accomplish in just 4 steps:

  • use ubuntu's usb-creator-gtk to make a usb-boot-stick using a ubuntu iso of your choice
  • on the usb-boot-stick, rename /boot/grub/loopback.cfg to /boot/grub/ubuntu_default.cfg
    • you can delete the pics directory if you want
  • use grml2usb –grub –grub-mbr to install the grml iso's of your choice on the same usb-boot-stick
  • boot from the stick, grub will prompt you with the ubuntu menu entries right after your grml boot entries
usb.txt · Last modified: 2012/10/08 14:40 by mika
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