/usr/sbin/elilo documentation

There are two parts to elilo:

/usr/lib/elilo/elilo.efi   The bootloader itself.
/usr/sbin/elilo            Utility to install/update a bootload configuration.

This document describes /usr/sbin/elilo; for information on elilo.efi, or
the configuration file format, please refer to /usr/doc/elilo/elilo.txt.


elilo option summary:

  -b, --boot                 set bootstrap partition device [ -b /dev/sda1 ]
  -i, --install              pathname to the actual bootloader binary
                               default: /usr/{local/}lib/elilo/elilo.efi
  -C, --config               use alternate configuration file [ -C config_file ]
      --autoconf             auto-generate a /etc/elilo.conf
      --efiboot              elilo auto configuration: create an efi boot
                               manager entry for elilo
      --timeout              elilo auto configuration: sets the time elilo
                               will wait for user input before booting default
                               image default: 20 (2 seconds)
      --image                elilo auto configuration: sets the path to the
                               kernel image. default: /vmlinuz
      --label                elilo auto configuration: sets the image label
                               default: Linux
      --root                 elilo auto configuration: sets the root device
                               default: /dev/sda3
      --format               create a new FAT filesystem on the boot partition
  -v, --verbose              make elilo more verbose
      --debug                print boring junk only useful for debugging
  -h, --help                 display this help and exit
  -V, --version              output version information and exit


The primary function of elilo is to copy files necessary for booting
Debian GNU/Linux from the main filesystem to a subdirectory /EFI/debian
on the boot partition.  In addition, elilo can create a default
configuration file, /etc/elilo.conf, and can invoke efibootmgr to create
an entry in the EFI Boot Manager menu such that a system will autoboot
in to Debian GNU/Linux on power up.

It is important to note that elilo will recreate the /EFI/debian
directory on your boot partition every time it is run, so any local
changes you might have made under that direcotry will be lost.  The
intention of elilo is to hide the boot partition from the user; the
partition is not normally mounted so the user is unlikely to make local
modifications.

elilo does various checks on the partition (e.g. must pass dosfsck, must
be a partition rather than a whole disk, must not be mounted, etc.)
before overwriting it.  Invoking it with --format will run mkdosfs on
the partition; this is generally not advisable, if the partition may be
shared with other operating systems.


/etc/elilo.conf generation:

This is generally only used during system installation.  Typically elilo.conf
will already exist, and is not modified by elilo.  To generate a new config
file, you must specify --autoconf, along with any of the other auto
configuration options necessary to override defaults.  Defaults are given
in the option summary above.


Invoking efibootmgr:

--efiboot will cause elilo to run efibootmgr and create a default boot entry
in the EFI Boot Manager menu called "Debian GNU/Linux".  Any other entries
of that name are assumed to be left over from some previous installation and
are deleted.  If the descriptions for the first two boot mansger entries
start with strings "floppy" and "CD" or "DVD", then the new boot entry
is created as the third entry, so that the system will still boot
exchangeable media first by default.


elilo.conf extensions:

elilo requires a couple of extra parameters in elilo.conf that elio.efi does
not currently support.  They are:

install=<path to elilo.efi>  # default /usr/lib/elilo/elilo.efi
boot=<boot partition>        # /dev/sda1

These are needed so that a normal run of elilo with no parameters can find 
the elilo.efi binary and boot partition in order to rebuild it.


Boot partition creation:

Once the /EFI/debian directory has been created, elilo copies various
files to it.  These include elilo.efi, elilo.conf, and certain kernel
and ramdisk images referenced by elilo.conf.  elilo.conf is modified as
it is copied, to comment out the install= and boot= lines so as not to
confuse elilo.efi, and to prefix any file paths with /EFI/debian.  All
kernel and initrd images that are referenced via standard UNIX paths are
copied to the boot partition, so that elilo.efi can find them easily.
Any paths containing a ':' are assumed to be EFI device paths, and as
such are not copied.  Device path names depend on features of elilo.efi,
but a typical path might be "scsi1:/vmlinux-2.4.7".  It is hoped that
eventually a sufficiently robust device path naming scheme will be
devised, and then devices paths will be used throughout, and it will no
longer be necessary to copy images to the boot partition.