system bootstrap configuration information
information on bootstrapping the system. Through it you can specify the kernel
to be booted, parameters to be passed to it, and additional modules to be
loaded; and generally set all variables described in
's format was defined
explicitly to resemble
and can be sourced by
some settings are treated in a special fashion. Also, the behavior of some
settings is defined by the setting's suffix; the prefix identifies which
module the setting controls.
The general parsing rules are:
- Spaces and empty lines are ignored.
- A # sign will mark the remainder of the line as a comment.
- Only one setting can be present on each line.
All settings have the following format:
Unless it belongs to one of the classes of settings that receive special
treatment, a setting will set the value of a
environment variable. The settings that receive special treatment are listed
below. Settings beginning with “*” below define the modules to
be loaded and may have any prefix; the prefix identifies a module. All such
settings sharing a common prefix refer to the same module.
- Immediately executes a
command. This type of setting cannot be processed by programs other than
so its use should be avoided. Multiple instances of it will be processed
- Defines additional configuration files to be processed right after the
- Name of the kernel to be loaded. If no kernel name is set, no additional
modules will be loaded. The name must be a subdirectory of
/boot that contains a kernel.
- Flags to be passed to the kernel.
- Specify the root partition to mount. For example:
automatically calculates the value of this tunable from
/etc/fstab from the partition the
kernel was loaded from. The calculated value might be calculated
incorrectly when /etc/fstab is not
startup (as during diskless booting from NFS), or if a different device is
desired by the user. The preferred value can be set in
The value can also be overridden from the
command line. This is useful for system recovery when
/etc/fstab is damaged, lost, or read
from the wrong partition.
- Protect boot menu with a password without interrupting
autoboot process. The password should
be in clear text format. If a password is set, boot menu will not appear
until any key is pressed during countdown period specified by
autoboot_delay variable or
autoboot process fails. In both cases
user should provide specified password to be able to access boot
- Provides a password to be required by check-password before execution is
allowed to continue. The password should be in clear text format. If a
password is set, the user must provide specified password to boot.
- If set to “YES”, module names will be displayed as they are
- Blacklist of modules. Modules specified in the blacklist may not be loaded
automatically with a *_load directive,
but they may be loaded directly at the
prompt. Blacklisted modules may still be loaded indirectly as dependencies
of other modules.
- If set to “YES”, that module will be loaded. If no name is
defined (see below), the module's name is taken to be the same as the
- Defines the name of the module.
- Defines the module's type. If none is given, it defaults to a kld
- Flags and parameters to be passed to the module.
- Commands to be executed before the module is loaded. Use of this setting
should be avoided.
- Commands to be executed after the module is loaded. Use of this setting
should be avoided.
- Commands to be executed if the loading of a module fails. Except for the
special value “abort”, which aborts the bootstrap process,
use of this setting should be avoided.
developers should never use these suffixes
for any kernel environment variables (tunables) or conflicts will result.
's default settings can be
ignored. The few of them which are important or useful are:
- (“NO”) If set to “YES”, a bitmap will be
loaded to be displayed on screen while booting.
- (“/boot/splash.bmp”) Name
of the bitmap to be loaded. Any other name can be used.
- (“9600” or the value of the
BOOT_COMCONSOLE_SPEED variable when
was compiled). Sets the speed of the serial console. If the previous boot
loader stage specified that a serial console is in use then the default
speed is determined from the current serial port speed setting.
- (“vidconsole”) “comconsole” selects serial
console, “vidconsole” selects the video console,
“nullconsole” selects a mute console (useful for systems
with neither a video console nor a serial port), and
“spinconsole” selects the video console which prevents any
input and hides all output replacing it with “spinning”
character (useful for embedded products and such).
- Specify the maximum desired resolution for the EFI console. The following
values are accepted:
- (“kernel kernel.old”) Space or comma separated list of
kernels to present in the boot menu.
- (“NO”) If set to “YES”, will load the splash
screen module, making it possible to display a bmp image on the screen
- (“NO”) If set to “YES”, will load the splash
screen module, making it possible to display a pcx image on the screen
- (“NO”) If set to “YES”, the vesa module will
be loaded, enabling bitmaps above VGA resolution to be displayed.
- If set to “YES”, the beastie boot menu will be skipped.
- Selects a desired logo in the beastie boot menu. Possible values are:
- If set to “NO”, the beastie boot menu will be displayed
without ANSI coloring.
- (“YES”) If set to “NO”, the very early
boot-time entropy file will not be loaded. See the entropy entries in
- (“/boot/entropy”) The name of the very early boot-time
entropy cache file.
- (“NO”) If set to “YES”, the microcode update
file specified by cpu_microcode_name will
be loaded and applied very early during boot. This provides functionality
but ensures that CPU features enabled by microcode updates can be used by
the kernel. The update will be re-applied automatically when resuming from
an ACPI sleep state. If the update file contains updates for multiple
processor models, the kernel will search for and extract a matching
update. Currently this setting is supported only on Intel
amd64 processors. It has no effect on
other processor types.
- A path to a microcode update file.
Other settings that may be used in
that have no default value:
- Specifies a comma-delimited list of FDT overlays to apply.
/boot/dtb/overlays is created by
default for overlays to be placed in.
- If set to “YES”, attempt to auto-detect kernels installed in
/boot. This is an option specific to
the Lua-based loader. It is not available in the default Forth-based
- default settings -- do not change this file.
- user defined settings.
- machine-specific settings for sites with a common loader.conf.
first appeared in
This manual page was written by Daniel C.
encounters a syntax error, so any options which are vital for booting a
particular system (i.e.
precede any experimental additions to