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Updating the BIOS of a Thinkpad X220 using Linux

After spending a day trying to figure out various grub, syslinux and memdisk options, I retreated to googling and quickly found this page on the lenovo support forum.  I am going to copy the contents here to make sure I don't lose them in the future.  All props go to the original author:

1. Get the bios update iso (8duj10uc.iso here) from the lenovo support site.

2. Get 'geteltorito' and extract the boot image from the iso (isobar.c probably works too)

$ wget ''

$ perl 8duj10uc.iso > biosupdate.img

3. Copy the image to the usb thumdrive

$ sudo dd if=biosupdate.img of=/dev/usbthumdrive bs=512K

Here is a copy of the script for posterity:



use Getopt::Std;

# a bootimage extractor
# Script that will extract the first El Torito bootimage from a
# bootable CD image
# R. Krienke 08/2001
# License: GPL
# Get latest version from:
# Version 0.5
#    2009/06/22
#    A patch for harddisk emulation images from .
#    For BootMediaType=4 (harddisk emulation) SectorCount is always 1, and
#    returns just MBR. This patch guesses the correct bootimage size
#    from MBR (offset+size of the first partitition).
# Version 0.4
#    2007/02/01
#    A patch from Santiago Garcia  to use a virtual sector
#    size (vSecSize) of 512 bytes, as defined on "El Torito" specs and change
#    unpack of the sector count from n to v to get the correct sector count.
# Version 0.3
#    2006/02/21
#    A patch from  Ben Collins  to make the
#    utility work on PPC machines (change from 'L'-encoding in pack to 'V')
# Version 0.2
#    Several patches included from Nathan Stratton Treadway(
#    to adjust the platform output as well as fixes for other minor bugs
# Version 0.1
#    Initial release
# For information on El Torito see


# Read a particular sector from a file
# sector counting starts at 0, not 1
sub getSector{
   my ($secNum, $secCount, $file)=@_;
   my ($sec, $count);

   open(FILE, $file) || die "Cannot open \"$file\" \n";

   seek(FILE, $secNum*$secSize, 0);
   $count=read(FILE, $sec, $vSecSize*$secCount, 0) ;
   if( $count != $vSecSize*$secCount ){
       warn "Error reading from file \"$file\"\n";


# Write eltorito data into a file
sub writeOutputFile{

   open(OUT, ">".$name)|| die "$0: Cannot open outputfile \"$name\" for writing. Stop.";
   print OUT $value;

# Usage
sub usage{
        warn "\n$0 [-hv] [-o outputfilename] cd-image \n",
            "Script will try to extract an El Torito image from a \n",
            "bootable CD (or cd-image) given by  and write \n",
            "the data extracted to STDOUT or to a file.\n",
            "   -h:        This help. \n",
            "   -v:        Print version of script and exit.\n",
            "   -o : Write extracted data to file  instead of STDOUT.\n",
        exit 0;

# ---------------------------------------------------------------------

if( defined($opt_v) ){
        warn "Version: $utilVersion \n";
        exit 0;

if( defined($opt_h) || $#ARGV <0 ){

if( defined($opt_o) ){


if( ! -r $imageFile ){
        die "Cannot read image/device \"$imageFile\". Aborting\n";

# Read Sector 17 from CD which should contain a Boot Record Volume
# descriptor. This descriptor contains at its start the text ($isoIdent)
# CD001     and ($toritoSpec)
# see
# for details

$sector=getSector(17, 1, $imageFile );
($boot, $isoIdent, $version, $toritoSpec,
        $unUsed, $bootP)= unpack( "Ca5CA32A32V", $sector );

if( $isoIdent ne "CD001" || $toritoSpec ne "EL TORITO SPECIFICATION" ){
        die "This data image does not seem to be a bootable CD-image\n";

# Now fetch the sector of the booting catalog
$sector=getSector($bootP, 1, $imageFile );

print STDERR "Booting catalog starts at sector: $bootP \n";

# The first 32 bytes of this sector contains the validation entry for a
# boot. The first byte has to be 01, the next byte determines the
# architecture the image is designed for, where 00 is i86, 01 is PowerPC
# and 02 is Mac. More data give info about manufacturer, etc.  The
# final two bytes must contain 0x55 and 0xAA respectively (as
# defined by the El Torito standard).

$validateEntry=substr($sector, 0, 32);

($header, $platform, $unUsed, $manufact, $unUsed, $five, $aa)=
               unpack( "CCvA24vCC", $validateEntry);

if( $header != 1 || $five != 0x55 || $aa != 0xaa ){
        die "Invalid Validation Entry on image \n";

print STDERR "Manufacturer of CD: $manufact\n";
print STDERR "Image architecture: ";
print STDERR "x86" if( $platform == 0 );
print STDERR "PowerPC" if( $platform == 1 );
print STDERR "Mac" if( $platform == 2 );
print STDERR "unknown ($platform)" if( $platform > 2 );
print STDERR "\n";

# Now we examine the initial/defaultentry which follows the validate
# entry and has a size of 32 bytes.

$initialEntry=substr($sector, 32, 32);

($boot, $media, $loadSegment, $systemType, $unUsed,
       $sCount, $imgStart, $unUsed)=unpack( "CCvCCvVC", $initialEntry);

if( $boot != 0x88 ){
        die "Boot indicator in Initial/Default-Entry is not 0x88. CD is not bootable. \n";

print STDERR "Boot media type is: ";
if( $media == 0 ){
        print STDERR "no emulation";
if( $media == 1 ){
        print STDERR "1.2meg floppy";
if( $media == 2 ){
        print STDERR "1.44meg floppy";
if( $media == 3 ){
        print STDERR "2.88meg floppy";
if( $media == 4 ){
        print STDERR "harddisk";
        $MBR=getSector($imgStart, 1, $imageFile );
        $partition1=substr($MBR, 446, 16);
        ($unUsed, $firstSector, $partitionSize) = unpack( "A8VV", $partition1);
        $count=$firstSector + $partitionSize;
print STDERR "\n";

# Only use the internal sector counter if the real size is unknown
# ($count==0)

print STDERR "El Torito image starts at sector $imgStart and has $cnt sector(s) of $vSecSize Bytes\n";

# We are there:
# Now read the bootimage to stdout
$image=getSector($imgStart, $cnt, $imageFile);

if( length($outputFilename) ){
   writeOutputFile($outputFilename, $image);
   print STDERR "\nImage has been written to file \"$outputFilename\".\n";
   print "$image";
   print STDERR "Image has been written to stdout ....\n";

References (6)

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Reader Comments (3)

Finally a recipe that works! x220 bios update, linux only and it works!

October 14, 2011 | Unregistered CommenterRicardo Reis

Also worked for my Lenovo Thinkpad T420 !

December 11, 2013 | Unregistered CommenterPawel

Some notes:

1. geteltorito from the genisoimage package in Ubuntu 13.10 works fine too

2. I was tempted to take a shortcut and boot the .iso (or the eltorito image) using GRUB and memdisk (from syslinux). This seems to work, but then the BIOS update utility hangs when you try to update the BIOS, after the first yellow confirmation prompt but before it shows the "don't unplug from AC" warning. Writing the eltorito image directly into a USB key works fine.

January 8, 2014 | Unregistered CommenterMarius Gedminas

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