Provided by: iucode-tool_0.8.3-1_i386 bug


       iucode_tool - Tool to manipulate Intel® IA32/X86_64 microcode bundles


       iucode_tool [options] [[-ttype] filename|dirname] ...


       iucode_tool is an utility that can load Intel® processor microcode data
       from files in both text and binary microcode bundle formats.

       It can output a list of the microcodes  in  these  files,  merge  them,
       upload  them  to  the  kernel  (to  upgrade the microcode in the system
       processor cores) or write some of them out to a file in  binary  format
       for later use.

       iucode_tool  will  load  all  microcodes  in  the  specified  files and
       directories to memory,  in  order  to  process  them.   Duplicated  and
       outdated microcodes will be discarded.  It can read microcode data from
       standard input (stdin), by specifying a file name of "-" (minus sign).

       Microcode data files are assumed to be in .dat text format if they have
       a  .dat  suffix,  and to be in binary format otherwise.  Standard input
       (stdin) is assumed to be in .dat text format.  The  -t  option  can  be
       used  to change the type of the files specified after it, including for

       If a directory is specified, all files whose names do not begin with  a
       dot  will  be  loaded,  in  unspecified  order.  Nested directories are

       You can select which  microcodes  should  be  written  out,  listed  or
       uploaded to the kernel using the -S, -s, --date-before and --date-after
       options.  Should none of those options  be  specified,  all  microcodes
       will be selected.

       You can upload the selected microcodes to the kernel, write them out to
       a file (in binary format) or  to  per-processor-signature  files  in  a
       directory using the -w, -k, and -K options.

       For  more information about Intel processor microcodes, please read the
       included documentation and the Intel manuals listed  in  the  SEE  ALSO


       iucode_tool accepts the following options:

       -q, --quiet
              Inhibit usual output.

       -v, --verbose
              Print more information.  Use more than once for added verbosity.

       -h, -?, --help
              List all available options and their meanings.

              Show summary of options.

       -V, --version
              Show version of program.

       -t type
              Sets the file type of the following files. type can be:

              b      binary  format.   This  is  the  same  format used by the
                     kernel driver and the BIOS/EFI,  which  is  described  in
                     detail  by  the Intel 64 and IA-32 Architectures Software
                     Developer's Manual, Volume 3A, section 9.11.

              d      Intel microcode .dat text format.   This  is  the  format
                     normally  used  by  Intel  to  distribute  microcode data

              a      (default) iucode_tool will use  the  filename  suffix  to
                     select  the  file  type:  .dat text format for files that
                     have a .dat suffix, and binary type otherwise.  Note that
                     for stdin, .dat text format is assumed.

              When multiple versions of the microcode for a specific processor
              are available from different files, keep the one from  the  file
              loaded  last,  regardless  of revision levels.  Files are always
              loaded in the order they were specified  in  the  command  line.
              This option has no effect when just one file has been loaded.

              When multiple versions of the microcode for a specific processor
              are available from  different  files,  keep  the  one  with  the
              highest revision level.  This is the default mode of operation.

              Perform  strict checks on the microcode data.  It will refuse to
              load microcodes and microcode data files  with  unexpected  size
              and metadata.  This is the default mode of operation.

              Perform  less  strict checks on the microcode data.  Use only if
              you happen to  come  across  a  microcode  data  file  that  has
              microcodes with weird sizes inside, or to load microcodes from a
              truncated microcode data file (in which case you will also  need
              the --ignore-broken option).

              Skip  broken  microcode entries during load, instead of aborting

              Abort program execution if a broken microcode  is  found  during
              load.  This is the default mode of operation.

       -s [!]signature[,pf_mask]
              Select  microcodes  by  the  specificed  signature and processor
              flags mask (pf_mask).  If pf_mask is specified, it  will  select
              only  microcodes  that  are  suitable  for  at  least one of the
              processor flag combinations in the mask.

              Specify more than once to select more microcodes.   This  option
              can  be  combined  with the -S option to select more microcodes.
              If signature is prefixed with a !, it will  unselect  microcodes
              instead.   Ordering  matters,  with  later -s options overriding
              earlier ones.

              The  --scan-system  option   has   precedence,   therefore   the
              microcodes it selects cannot be unselected.

       -S, --scan-system
              Select  microcodes  by  scanning  all  online processors on this
              system for their signatures.

              This option can be combined with the -s option  to  select  more

              Should  the  scan  fail, the program will print a warning to the
              user and continue as if --scan-system had not been specified.

       --date-before=YYYY-MM-DD and --date-after=YYYY-MM-DD
              Limit the selected microcodes by a date range.  The date must be
              given  in  ISO  format,  with  four  digits for the year and two
              digits for the month and day and - for the separator.  Dates are
              not  range-checked,  so  you  can use --date-after=2000-00-00 to
              select all microcodes dated since January 1st, 2000.

       -l, --list
              List selected microcode signatures.

       -L, --list-all
              List all microcode signatures while they're being processed.

       -k[device], --kernel[=device]
              Upload selected  microcodes  to  the  kernel.   Optionally,  the
              device  path  can  be  specified  (default: /dev/cpu/microcode).
              This update method is being deprecated.

       -K[directory], --write-firmware[=directory]
              Write selected microcodes with the  filenames  expected  by  the
              Linux  kernel  firmware  loader.   Optionally,  the  destination
              directory can be specified (default: /lib/firmware/intel-ucode).

       -wfile, --write-to=file
              Write selected microcodes to a file in binary format.

              Remove  the  destination  file  before  writing.   Without  this
              option,  iucode_tool  will abort if the file already exists.  Do
              note that it will remove symlinks instead of following them.

              Abort if the destination  file  already  exists.   This  is  the
              default  mode  of  operation.  Do note that iucode_tool does not
              follow symlinks when writing files.


       iucode_tool reads all data to memory before doing any processing.

       The microcode data is sorted by cpu  signature.   Older  revisions  are
       removed (either based on revision level or load order, depending on the
       --downgrade option) before the data is written to a file or uploaded to
       the kernel.

       Intel  microcode  data  files,  both in binary and text formats, can be
       concatenated to generate a bigger and still valid microcode data file.

       iucode_tool does not follow symlinks when writing microcode data  files
       (--write-to  and  --write-firmware  options).  It will either refuse to
       write the file and abort (default mode of  operation),  or  remove  the
       symlink  before  writing  (when  the --overwrite option is active).  It
       does follow directory symlinks to locate the directory to  write  files

   Linux Notes
       The cpuid kernel driver is required for the --scan-system functionality
       to work.

       Each Intel processor microcode must be uploaded through a single  write
       syscall  to  /dev/cpu/microcode,  but  more  than  one microcode can be
       uploaded per write syscall.  Writing the microcode to the kernel device
       will  update  all system processor cores at once.  This method is being
       deprecated and does not work on other system processor types.

       The old Linux firmware interface for  microcode  updates  needs  to  be
       triggered   on   a   per-core   basis,  by  writing  the  number  1  to
       /sys/devices/system/cpu/*/microcode/reload.    Depending   on    kernel
       version,  you must either trigger it on every core to avoid a dangerous
       situation where some cores are using outdated microcode, or the  kernel
       will  accept  the  request  only  for  the boot processor and use it to
       trigger an update on all system processor cores.

       Since Linux v3.6, the per-core interface has been replaced with  a  new
       interface  that  explicitly  triggers  an update for every core at once
       when       the       number        1        is        written        to

       The  microcode  driver should not be unloaded unless you are sure it is
       not going to be needed.  The driver needs to be loaded in order for the
       kernel  to  reapply the microcode updates after the system resumes from
       suspend or hibernation, and also to update any system  processor  cores
       that were off-line at the time the update was applied.


   Updating files in /lib/firmware/intel-ucode:
              iucode_tool   -K/lib/firmware/intel-ucode   /lib/firmware/intel-
              ucode/* /tmp/file-with-new-microcodes.bin

   Processing several compressed files at once:
              zcat intel-microcode*.dat.gz | iucode-tool -k -

              zcat intel-microcode*.bin.gz | iucode-tool -k -tb -


       iucode_tool will waste space  when  writing  microcodes  with  extended
       signatures (one copy per signature).

       The  extended  signature code is completely untested, and likely buggy.
       Intel so far has never  distributed  microcode  data  files  using  the
       extended signatures.

       Microcode with negative revision numbers is not special-cased, and will
       not be preferred over regular microcode.


       The Intel 64  and  IA-32  Architectures  Software  Developer's  Manual,
       Volume  3A:  System  Programming  Guide,  Part 1 (order number 253668),
       section 9.11.


       Henrique de Moraes Holschuh <>