Provided by: syslinux_6.04~git20190206.bf6db5b4+dfsg1-2_amd64 bug


       syslinux - install the SYSLINUX bootloader on a FAT filesystem


       syslinux [OPTIONS] device


       Syslinux  is  a  boot  loader  for  the  Linux  operating system which operates off an MS-
       DOS/Windows FAT filesystem. It is intended to simplify first-time installation  of  Linux,
       and for creation of rescue and other special-purpose boot disks.

       In  order  to  create  a  bootable  Linux  floppy  using Syslinux, prepare a normal MS-DOS
       formatted floppy. Copy one or more Linux kernel files to it, then execute the command:

              syslinux --install /dev/fd0

       This will alter the boot sector on the disk and copy a file  named  ldlinux.sys  into  its
       root directory.

       On boot time, by default, the kernel will be loaded from the image named LINUX on the boot
       floppy.  This default can be changed, see the section on the syslinux configuration file.

       If the Shift or Alt keys are held down during boot, or the Caps or Scroll locks  are  set,
       syslinux  will  display  a  lilo(8) -style "boot:" prompt. The user can then type a kernel
       file name followed by any kernel parameters. The SYSLINUX bootloader does not need to know
       about the kernel file in advance; all that is required is that it is a file located in the
       root directory on the disk.

       Syslinux supports the loading of initial ramdisks (initrd) and the bzImage kernel format.


       -i, --install
              Install SYSLINUX on a new medium, overwriting any previously installed bootloader.

       -U, --update
              Install SYSLINUX on a new medium if and only if a version of  SYSLINUX  is  already

       -s, --stupid
              Install  a  "safe,  slow  and stupid" version of SYSLINUX. This version may work on
              some very buggy BIOSes on which SYSLINUX would  otherwise  fail.   If  you  find  a
              machine on which the -s option is required to make it boot reliably, please send as
              much info about your machine as you can, and include the failure mode.

       -f, --force
              Force install even if it appears unsafe.

       -r, --raid
              RAID mode.  If boot fails, tell the BIOS to  boot  the  next  device  in  the  boot
              sequence  (usually  the  next hard disk) instead of stopping with an error message.
              This is useful for RAID-1 booting.

       -d, --directory subdirectory
              Install the SYSLINUX control files  in  a  subdirectory  with  the  specified  name
              (relative to the root directory on the device).

       -t, --offset offset
              Indicates that the filesystem is at an offset from the base of the device or file.

       --once command
              Declare a boot command to be tried on the first boot only.

       -O, --clear-once
              Clear the boot-once command.

       -H, --heads head-count
              Override the detected number of heads for the geometry.

       -S, --sectors sector-count
              Override the detected number of sectors for the geometry.

       -z, --zipdrive
              Assume zipdrive geometry (--heads 64 --sectors 32).


   Configuration file
       All  the  configurable  defaults  in  SYSLINUX  can  be  changed  by putting a file called
       syslinux.cfg in the install directory of the boot disk. This is a text file in either UNIX
       or  DOS  format,  containing  one  or more of the following items (case is insensitive for

       This list is out of date.

       In the configuration file blank lines and comment lines beginning with a hash mark (#) are

       default kernel [ options ... ]
              Sets the default command line. If syslinux boots automatically, it will act just as
              if the entries after "default" had been typed in at the "boot:" prompt.

              If no DEFAULT or UI statement is  found,  or  the  configuration  file  is  missing
              entirely,  SYSLINUX drops to the boot: prompt with an error message (if NOESCAPE is
              set, it stops with a "boot failed" message; this is also the case for  PXELINUX  if
              the configuration file is not found.)

       NOTE: Until SYSLINUX 3.85, if no configuration file is present, or no
              "default" entry is present in the configuration file, the default is "linux auto".

       Even earlier versions of SYSLINUX used to automatically
              append  the string "auto" to whatever the user specified using the DEFAULT command.
              As of version 1.54, this is no longer true, as it  caused  problems  when  using  a
              shell as a substitute for "init."  You may want to include this option manually.

       append options ...
              Add  one  or  more  options  to  the  kernel command line. These are added both for
              automatic and manual boots. The options are added at  the  very  beginning  of  the
              kernel  command  line,  usually  permitting  explicitly  entered  kernel options to
              override them. This is the equivalent of the lilo(8)
               "append" option.

       label label
         kernel image
         append options ...
              Indicates that if label is entered as the kernel to boot, syslinux  should  instead
              boot  image,  and the specified "append" options should be used instead of the ones
              specified in the global section of the file (before the first "label" command.) The
              default  for image is the same as label, and if no "append" is given the default is
              to use the global entry (if any).  Use "append -" to use no options at all.  Up  to
              128 "label" entries are permitted.

                     The  "image" doesn't have to be a Linux kernel; it can be a boot sector (see

       implicit flag_val
              If flag_val is 0, do not load a kernel image unless it has been explicitly named in
              a "label" statement.  The default is 1.

       timeout timeout
              Indicates  how  long  to wait at the "boot:" prompt until booting automatically, in
              units of 1/10 s. The timeout is cancelled as soon as the user types anything on the
              keyboard, the assumption being that the user will complete the command line already
              begun. A timeout of zero will disable the timeout  completely,  this  is  also  the
              default.  The  maximum possible timeout value is 35996; corresponding to just below
              one hour.

       serial port [ baudrate ]
              Enables a serial port to act as the console. "port" is a number (0 =  /dev/ttyS0  =
              COM1,  etc.);  if  "baudrate"  is omitted, the baud rate defaults to 9600 bps.  The
              serial parameters are hardcoded to be 8 bits, no parity, 1 stop bit.

              For this directive to be guaranteed to  work  properly,  it  should  be  the  first
              directive in the configuration file.

       font filename
              Load a font in .psf format before displaying any output (except the copyright line,
              which is output as ldlinux.sys itself is loaded.) syslinux only loads the font onto
              the video card; if the .psf file contains a Unicode table it is ignored.  This only
              works on EGA and VGA cards; hopefully it should do nothing on others.

       kbdmap keymap
              Install a simple keyboard map. The keyboard remapper used is  very  simplistic  (it
              simply  remaps  the  keycodes received from the BIOS, which means that only the key
              combinations relevant in the default layout  -  usually  U.S.   English  -  can  be
              mapped)  but  should  at  least  help  people  with  AZERTY keyboard layout and the
              locations of = and , (two special characters  used  heavily  on  the  Linux  kernel
              command line.)

              The included program from the lilo(8)
               distribution can be used to create such keymaps.

       display filename
              Displays the indicated file on the screen at boot time (before the boot: prompt, if
              displayed). Please see the section below on DISPLAY files. If the file is  missing,
              this option is simply ignored.

       prompt flag_val
              If  flag_val  is  0,  display  the  "boot:"  prompt only if the Shift or Alt key is
              pressed, or Caps Lock or Scroll lock is set (this is the default).  If flag_val  is
              1, always display the "boot:" prompt.

       f1 filename
       f2 filename
       f9 filename
       f10 filename
       f11 filename
       f12 filename
              Displays  the  indicated  file  on the screen when a function key is pressed at the
              "boot:" prompt. This can be used to implement pre-boot online help (presumably  for
              the kernel command line options.)

              When  using  the  serial console, press <Ctrl-F><digit> to get to the help screens,
              e.g. <Ctrl-F>2 to get to the f2 screen.  For  f10-f12,  hit  <Ctrl-F>A,  <Ctrl-F>B,
              <Ctrl-F>C.   For  compatiblity  with  earlier  versions, f10 can also be entered as

   Display file format
       DISPLAY and function-key help files are text files in either DOS or UNIX format  (with  or
       without <CR>). In addition, the following special codes are interpreted:

       <FF> = <Ctrl-L> = ASCII 12
              Clear the screen, home the cursor.  Note that the screen is filled with the current
              display color.

       <SI><bg><fg>, <SI> = <Ctrl-O> = ASCII 15
              Set the display colors to the specified background  and  foreground  colors,  where
              <bg> and <fg> are hex digits, corresponding to the standard PC display attributes:

              0 = black          8 = dark grey
              1 = dark blue      9 = bright blue
              2 = dark green     a = bright green
              3 = dark cyan      b = bright cyan
              4 = dark red       c = bright red
              5 = dark purple    d = bright purple
              6 = brown          e = yellow
              7 = light grey     f = white

              Picking  a  bright color (8-f) for the background results in the corresponding dark
              color (0-7), with the foreground flashing.

              colors are not visible over the serial console.

       <CAN>filename<newline>, <CAN> = <Ctrl-X> = ASCII 24
              If a VGA display is present, enter graphics mode and display the  graphic  included
              in  the  specified  file.   The  file  format is an ad hoc format called LSS16; the
              included Perl program "ppmtolss16" can be used to produce these images.  This  Perl
              program also includes the file format specification.

              The  image  is  displayed  in  640x480  16-color  mode.  Once in graphics mode, the
              display attributes (set by <SI> code  sequences)  work  slightly  differently:  the
              background  color is ignored, and the foreground colors are the 16 colors specified
              in the image file.  For that reason, ppmtolss16 allows you to specify that  certain
              colors should be assigned to specific color indicies.

              Color  indicies  0  and  7,  in  particular,  should  be chosen with care: 0 is the
              background color, and 7 is the color used for the text printed by SYSLINUX itself.

       <EM>, <EM> = <Ctrl-U> = ASCII 25
              If we are currently in graphics mode, return to text mode.

       <DLE>..<ETB>, <Ctrl-P>..<Ctrl-W> = ASCII 16-23
              These codes can be used to select which modes  to  print  a  certain  part  of  the
              message  file  in.  Each of these control characters select a specific set of modes
              (text screen, graphics screen, serial  port)  for  which  the  output  is  actually

              Character                       Text    Graph   Serial
              <DLE> = <Ctrl-P> = ASCII 16     No      No      No
              <DC1> = <Ctrl-Q> = ASCII 17     Yes     No      No
              <DC2> = <Ctrl-R> = ASCII 18     No      Yes     No
              <DC3> = <Ctrl-S> = ASCII 19     Yes     Yes     No
              <DC4> = <Ctrl-T> = ASCII 20     No      No      Yes
              <NAK> = <Ctrl-U> = ASCII 21     Yes     No      Yes
              <SYN> = <Ctrl-V> = ASCII 22     No      Yes     Yes
              <ETB> = <Ctrl-W> = ASCII 23     Yes     Yes     Yes

              For example:
              <DC1>Text mode<DC2>Graphics mode<DC4>Serial port<ETB>
               ... will actually print out which mode the console is in!

       <SUB> = <Ctrl-Z> = ASCII 26
              End of file (DOS convention).

   Other operating systems
       This version of syslinux supports chain loading of other operating systems (such as MS-DOS
       and its derivatives, including Windows 95/98).

       Chain loading requires the boot sector of the foreign operating system to be stored  in  a
       file  in  the  root  directory of the filesystem.  Because neither Linux kernels, nor boot
       sector images have reliable magic numbers, syslinux will look at the file  extension.  The
       following extensions are recognised:

       none or other    Linux kernel image
       BSS              Boot sector (DOS superblock will be patched in)
       BS               Boot sector

       For  filenames  given  on  the  command  line, syslinux will search for the file by adding
       extensions in the order listed above if the plain filename  is  not  found.  Filenames  in
       KERNEL statements must be fully qualified.

   Novice protection
       Syslinux  will  attempt  to  detect  if the user is trying to boot on a 286 or lower class
       machine, or a machine with less than 608K of low ("DOS") RAM (which means the  Linux  boot
       sequence  cannot  complete).  If so, a message is displayed and the boot sequence aborted.
       Holding down the Ctrl key while booting disables this feature.

       The compile time and date of a specific syslinux  version  can  be  obtained  by  the  DOS
       command  "type  ldlinux.sys". This is also used as the signature for the LDLINUX.SYS file,
       which must match the boot sector

       Any file that syslinux uses can be marked hidden, system or readonly if so is  convenient;
       syslinux  ignores  all  file  attributes.   The  SYSLINUX installed automatically sets the
       readonly attribute on LDLINUX.SYS.

   Bootable CD-ROMs
       SYSLINUX can be used to create bootdisk images for El Torito-compatible bootable  CD-ROMs.
       However, it appears that many BIOSes are very buggy when it comes to booting CD-ROMs. Some
       users have reported that the following steps are  helpful  in  making  a  CD-ROM  that  is
       bootable on the largest possible number of machines:

       •      Use the -s (safe, slow and stupid) option to SYSLINUX

       •      Put  the  boot  image  as  close  to  the  beginning  of the ISO 9660 filesystem as

       A CD-ROM is so much faster than a floppy that the -s option shouldn't matter from a  speed

       Of  course,  you  probably  want  to  use  ISOLINUX  instead.   See the documentation file

   Booting from a FAT partition on a hard disk
       SYSLINUX can boot from a FAT filesystem partition on a hard disk  (including  FAT32).  The
       installation  procedure  is  identical to the procedure for installing it on a floppy, and
       should work under either DOS or Linux. To boot from a  partition,  SYSLINUX  needs  to  be
       launched  from  a Master Boot Record or another boot loader, just like DOS itself would. A
       sample master boot sector (mbr.bin) is included with SYSLINUX.


       I would appreciate hearing of any problems you have with SYSLINUX.  I would also  like  to
       hear from you if you have successfully used SYSLINUX, especially if you are using it for a

       If you are reporting problems, please include all possible information about  your  system
       and  your BIOS; the vast majority of all problems reported turn out to be BIOS or hardware
       bugs, and I need as much information as possible in order to diagnose the problems.

       There is a mailing list for discussion among SYSLINUX users and for announcements  of  new
       and test versions. To join, send a message to with the line:

       subscribe syslinux

       in the body of the message. The submission address is


       lilo(8),, fdisk(8), mkfs(8), superformat(1).


       This  manual page is a modified version of the original syslinux documentation by H. Peter
       Anvin  <>.  The  conversion  to  a  manpage   was   made   by   Arthur   Korn