Provided by: syslinux-legacy_3.63+dfsg-2ubuntu9_amd64 bug


       syslinux - install the SYSLINUX bootloader on a FAT filesystem


       syslinux [-sfr] [-d directory] [-o offset] 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 /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 loader 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.


       -s     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 install even if it appears unsafe.

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

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


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

       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  configuration  file  is  present,  or  no "default" entry is present in the
              configuration file, the default is "linux auto".

       NOTE: 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.

              Notes: Labels are mangled as if they were DOS filenames, and must be  unique  after
                     mangling.   For  example,  two  labels  "v2.1.30"  and "v2.1.31" will not be

                     The "image" doesn't have to be a Linux kernel; it can be a boot sector or  a
                     COMBOOT file (see below.)

       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).

   Comboot Images and 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),  as  well  as COMBOOT-style standalone
       executables (a subset of DOS .COM files; see separate section below.)

       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, boot sector
       images, nor COMBOOT files have reliable magic numbers, syslinux  will  look  at  the  file
       extension. The following extensions are recognised:

       none or other    Linux kernel image
       CBT              COMBOOT image (not runnable from DOS)
       BSS              Boot sector (DOS superblock will be patched in)
       BS               Boot sector
       COM              COMBOOT image (runnable from DOS)

       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.

       A  COMBOOT  file  is  a  standalone  executable  in DOS .COM format. They can, among other
       things, be produced by the Etherboot package by Markus Gutschke and Ken Yap. The following
       requirements apply for these files to be sufficiently "standalone" for syslinux to be able
       to load and run them:

       ·      The program must not execute any DOS calls (since there is no DOS), although it may
              call  the  BIOS.  The  only  exception  is  that  the  program  may execute INT 20h
              (Terminate Program) to return to the syslinux prompt. Note especially that INT  21h
              AH=4Ch, INT 21h AH=31h or INT 27h are not supported.

       ·      Only  the  fields  pspInt20  at  offset  00h,  pspNextParagraph  at  offset 02h and
              pspCommandTail at offset 80h (contains the  arguments  from  the  syslinux  command
              line) in the PSP are supported. All other fields will contain zero.

       ·      The  program  must not modify any main memory outside its 64K segment if it returns
              to syslinux via INT 20h.

       Syslinux currently doesn't provide any form of API for the use of COMBOOT files.  If there
       is  need, a future version may contain an INT interface to some syslinux functions; please
       contact me if you have a need or ideas for such an API.

   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