ae3096705c
boot0.S changes: + import a patch from Christoph Mallon to rearrange the various print functions and save another couple of bytes; + implement the suggestion in PR 70531 to enable booting from any valid partition because even the extended partitions that were previously in our kill list may contain a valid boot loader. This simplifies the code and saves some bytes; + followwing up PR 127764, implement conditional code to preserve the 'Volume ID' which might be used by other OS (NT, XP, Vista) and is located at offset 0x1b8. This requires a relocation of the parameter block within the boot sector -- there is no other possible workaround. To address this, boot0cfg has been updated to handle both versions of the boot code; + slightly rearrange the strings printed in the menus to make the code buildable with all options. Given the tight memory budget, this means that with certain options we need to shrink or remove certain labels. and especially: make -DVOLUME_LABEL -DPXE the default options. This means that the newly built boot0 block will preserve the Volume ID, and has the (hidden) option F6 to boot from INT18/PXE. I think the extra functionality is well worth the change. The most visible difference here is that the 'Default: ' string now becomes 'Boot: ' (it can be reverted to the old value but then we need to nuke 1/2 partition name or entries to make up for the extra room). boot0cfg changes: + modify the code to recognise the new boot0 structure (with the relocated options block to make room for the Volume id). + add two options, '-i xxxx-xxxx' to set the volume ID, -e c to modify the character printed in case of bad input PR: 127764 70531 Submitted by: Christoph Mallon (portions) MFC after: 4 weeks
210 lines
5.9 KiB
Groff
210 lines
5.9 KiB
Groff
.\" Copyright (c) 1999 Robert Nordier
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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.\" OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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.\" OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd June 7, 2007
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.Dt BOOT0CFG 8
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.Os
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.Sh NAME
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.Nm boot0cfg
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.Nd boot manager installation/configuration utility
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.Sh SYNOPSIS
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.Nm
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.Op Fl Bv
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.Op Fl b Ar boot0
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.Op Fl d Ar drive
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.Op Fl e Ar bell character
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.Op Fl f Ar file
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.Op Fl i Ar volume-id
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.Op Fl m Ar mask
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.Op Fl o Ar options
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.Op Fl s Ar slice
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.Op Fl t Ar ticks
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.Ar disk
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.Sh DESCRIPTION
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The
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.Fx
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.Sq boot0
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boot manager permits the operator to select from which disk and
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slice an i386 machine (PC) is booted.
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.Pp
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Note that what are referred to here as
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.Dq slices
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are typically called
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.Dq partitions
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in
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.No non- Ns Bx
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documentation relating to the PC.
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Typically, only non-removable disks are sliced.
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.Pp
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The
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.Nm
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utility optionally installs the
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.Sq boot0
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boot manager on the specified
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.Ar disk ;
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and allows various operational parameters to be configured.
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.Pp
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On PCs, a boot manager typically occupies sector 0 of a disk, which is
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known as the Master Boot Record (MBR).
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The MBR contains both code (to which control is passed by the PC BIOS)
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and data (an embedded table of defined slices).
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.Pp
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The options are:
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.Bl -tag -width indent
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.It Fl B
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Install the
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.Sq boot0
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boot manager.
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This option causes MBR code to be replaced, without
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affecting the embedded slice table.
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.It Fl b Ar boot0
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Specify which
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.Sq boot0
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image to use.
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The default is
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.Pa /boot/boot0
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which will use the video card as output, alternatively
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.Pa /boot/boot0sio
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can be used for output to the COM1 port.
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(Be aware that nothing will be output to the COM1 port unless the
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modem signals DSR and CTS are active.)
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.It Fl d Ar drive
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Specify the drive number used by the PC BIOS in referencing the drive
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which contains the specified
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.Ar disk .
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Typically this will be 0x80 for the first hard drive, 0x81 for the
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second hard drive, and so on; however any integer between 0 and 0xff
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is acceptable here.
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.It Fl e Ar bell character
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Set the character to be printed in case of input error.
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.It Fl f Ar file
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Specify that a backup copy of the preexisting MBR should be written to
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.Ar file .
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This file is created if it does not exist, and replaced if it does.
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.It Fl i Ar volume-id
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Specifies a volume-id (in the form XXXX-XXXX) to be saved at location
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0x1b8 in the MBR. This information is sometimes used by NT, XP and Vista
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to identify the disk drive. The option is only compatible with version 2.00
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of the 512-byte boot block.
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.It Fl m Ar mask
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Specify slices to be enabled/disabled, where
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.Ar mask
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is an integer between 0 (no slices enabled) and 0xf (all four slices
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enabled).
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.It Fl o Ar options
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A comma-separated string of any of the following options may be
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specified (with
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.Dq no
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prepended as necessary):
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.Bl -tag -width indent
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.It packet
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Use the disk packet (BIOS INT 0x13 extensions) interface,
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as opposed to the legacy (CHS) interface, when doing disk I/O.
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This allows booting above cylinder 1023, but requires specific
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BIOS support.
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The default is
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.Sq packet .
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.It setdrv
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Forces the drive containing the disk to be referenced using drive
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number definable by means of the -d option.
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The default is
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.Sq nosetdrv .
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.It update
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Allow the MBR to be updated by the boot manager.
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(The MBR may be updated to flag slices as
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.Sq active ,
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and to save slice selection information.)
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This is the default; a
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.Sq noupdate
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option causes the MBR to be treated as read-only.
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.El
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.It Fl s Ar slice
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Set the default boot selection to
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.Ar slice .
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Values between 1 and 4 refer to slices; a value of 5 refers to the
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option of booting from a second disk.
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.It Fl t Ar ticks
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Set the timeout value to
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.Ar ticks .
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(There are approximately 18.2 ticks per second.)
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.It Fl v
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Verbose: display information about the slices defined, etc.
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.El
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.Sh FILES
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.Bl -tag -width /boot/boot0sio -compact
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.It Pa /boot/boot0
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The default
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.Sq boot0
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image
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.It Pa /boot/boot0sio
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Image for serial consoles (COM1,9600,8,N,1,MODEM)
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.El
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.Sh EXIT STATUS
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.Ex -std
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.Sh EXAMPLES
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To boot slice 2 on the next boot:
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.Pp
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.Dl "boot0cfg -s 2 ad0"
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.Pp
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To enable just slices 1 and 2 in the menu:
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.Pp
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.Dl "boot0cfg -m 0x3 ad0"
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.Pp
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To go back to non-interactive booting, use
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.Xr fdisk 8
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to install the default MBR:
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.Pp
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.Dl "fdisk -B ad0"
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.Pp
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.Sh SEE ALSO
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.Xr geom 4 ,
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.Xr boot 8 ,
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.Xr fdisk 8
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.Sh AUTHORS
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.An Robert Nordier Aq rnordier@FreeBSD.org .
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.Sh BUGS
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Protection mechanisms in the
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.Xr geom 4
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subsystem might prevent
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.Nm
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from being able to update the MBR on a mounted disk.
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Instructions for temporarily disabling these protection mechanisms
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can be found in the
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.Xr geom 4
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manpage.
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.Pp
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Use of the
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.Sq packet
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option may cause
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.Sq boot0
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to fail, depending on the nature of BIOS support.
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.Pp
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Use of the
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.Sq setdrv
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option with an incorrect -d operand may cause the MBR to be written
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to the wrong disk.
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Be careful!
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