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       microcode_ctl - microcode utility for Intel IA32 processors


       microcode_ctl [-h] [-u] [-q] [-Q] [-f microcode]


       The  microcode_ctl  utility is a companion to the IA32 microcode driver
       written by Tigran Aivazian <>.  The  utility
       has two uses:

       a)  it  decodes  and  sends  new  microcode  to the kernel driver to be
       uploaded to Intel IA32 processors. (Pentium Pro,  PII,  Celeron,  PIII,
       Xeon, Pentium 4 etc)

       b)  it  signals the kernel driver to release the buffers containing the
       copy of microcode data actually applied to given CPU, linear  array  of
       2048 bytes per CPU, see struct microcode in include/asm/processor.h for
       information on the layout of chunks buffers may hold

       The microcode update is volatile and  needs  to  be  uploaded  on  each
       system boot i.e. it doesn’t reflash your cpu permanently, reboot and it
       reverts back to the old microcode.

       -h     display usage and exit

       -u     upload microcode (from default filename)

       -f     upload microcode from named Intel formatted file

       -q     run silently when successful

       -Q     run silently even on failure


       microcode_ctl -u
              Upload microcode using defaults


              The default microcode location


       Microcode utility written by Simon Trimmer
       Linux Kernel driver written by Tigran Aivazian.


       Report bugs to either Simon  Trimmer  <>  or  Tigran
       Aivazian <>


       Copyright © 2000 VERITAS Software
       This is free software; see the source for copying conditions.  There is
       NO warranty; not even for MERCHANTABILITY or FITNESS FOR  A  PARTICULAR


       Thanks  to  the  Intel Corporation, for supplying microcode update data
       and publishing the specifications that enabled us  to  write  microcode
       driver for Linux.


       The brave are recommended to view the driver source code located in the
       Linux Kernel source tree in arch/i386/kernel/microcode.c

       Visit  for  more  information  and
       microcode updates.