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BOOT.CONFIG(5)		      File Formats Manual		BOOT.CONFIG(5)

NAME
       boot.config -- Configuration file for the legacy	boot blocks

DESCRIPTION
       The boot.config file contains options for the FreeBSD boot block	code.

       When  the first-	and second-stage FreeBSD boot loaders run, they	search
       the "a" slice of	the boot partition for a boot.config file  (as	a  re-
       sult,  slices which are missing an "a" partition	require	user interven-
       tion during the boot process).  If the boot.config file is  found,  its
       contents	 are  used  as	the default configuration options for the boot
       block code and are echoed to the	system console.

       A valid format of this file is to put BIOS drive	number,	 a  controller
       type,  a	 unit  number,	a partition, a kernel file name, and any other
       valid boot(8) option on a single	line, as it is	done  at  the  "boot:"
       prompt.

       The options related to the boot image selection described below and all
       the other options available for boot.config are documented in detail in
       the boot(8) manual page.

FILES
       /boot.config  parameters	for the	boot blocks (optional)
       /boot/config  alternate location	for boot config	information

EXAMPLES
       The command:

	     # echo "-P" > /boot.config

       will  activate the serial console of FreeBSD if no keyboard is present,
       otherwise video console will be used.

       The command:

	     # echo "1:ad(1,a)/boot/loader" > /boot.config

       will instruct the second	stage of boot(8) on the	 first	disk  to  boot
       with the	third boot(8) stage from the second disk.

       The command:

	     # echo "1:ad(1,a)/boot/loader -P" > /boot.config

       will do both of the above.

SEE ALSO
       boot(8),	loader(8)

AUTHORS
       This manual page	was written by Daniel Gerzo <danger@FreeBSD.org>.

FreeBSD	ports 15.quarterly     November	14, 2025		BOOT.CONFIG(5)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=boot.config&sektion=5&manpath=FreeBSD+15.1-RELEASE+and+Ports.quarterly>

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