man/man8/installboot.8

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.\" Copyright 2021 Toomas Soome <tsoome@me.com>
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.Dd Oct 16, 2021
.Dt INSTALLBOOT 8
.Os
.Sh NAME
.Nm installboot
.Nd install bootloader in a disk partition
.Sh SYNOPSIS
.Ss SPARC
.Nm
.Op Fl fn
.Op Fl F Sy zfs Ns | Ns Sy ufs Ns | Ns Sy hsfs
.Op Fl u Ar verstr
.Ar bootblk raw-device
.Nm
.Op Fl enV
.Fl F Sy zfs
.Fl i
.Ar raw-device | Ar file
.Nm
.Op Fl n
.Fl F Sy zfs
.Fl M
.Ar raw-device attach-raw-device
.Ss x86
.Nm
.Op Fl fFmn
.Op Fl b Ar boot_dir
.Op Fl u Ar verstr
.Op Ar stage1 stage2
raw-device
.Nm
.Op Fl enV
.Fl i
.Ar raw-device | Ar file
.Nm
.Op Fl n
.Fl M
.Ar raw-device attach-raw-device
.Sh DESCRIPTION
The
.Xr boot 8
boot program is loaded from disk and is responsible of loading kernel and its
support files from specific file system.
.Pp
The SPARC systems have one boot loader program file to be installed on the boot
area of a disk slice.
As the SPARC zfs boot loader is too large to fit into boot area at the start of
the disk slice,
.Nm
command will split the zfs boot loader between disk slice boot area, and zfs
pool boot area.
.Pp
The x86 BIOS systems have boot loader implemented as three stages:
.Bl -tag -width Ds
.It Sy stage1
.Pa /boot/pmbr
is used as master boot record
.Pq MBR
and partition boot program.
.It Sy stage2
.Pa /boot/gptzfsboot
is responsible for loading files from file system.
The
.Sy stage2
on x86 systems is always installed to zfs pool boot area, and therefore only zfs
boot is supported.
.Nm
command will record the location of
.Sy stage2
to
.Sy stage1 ,
which is always installed at least on partition
.Pq MBR or GPT
boot area, making it possible to boot via chainload from other boot loaders.
.Pp
When
.Nm
command is used with the
.Fl m
option,
.Nm
installs the stage1 file on the master boot sector of the disk as well.
.It Sy stage3
.Pa /boot/loader
is read from file system and executed by
.Sy stage2
and will provide boot loader user environment and is responsible of loading
and starting the operating system kernel.
.Pp
In case of GPT partitioning scheme, if the file system to boot from is either
UFS or PCFS, there must be
.Sy boot
partition defined to store stage2 boot program.
This is needed because UFS and PCFS do not have sufficient space reserved to
store boot programs.
.Pp
The boot partition must use following GPT UUID:
.Bd -literal -offset indent
6a82cb45-1dd2-11b2-99a6-080020736631
.Ed
.Pp
which is provided by
.Qq boot
tag in
.Xr format 8
partition menu.
.El
.Pp
The x86 UEFI systems load and start boot loader program from
.Sy /EFI/Boot
directory of the EFI System Partition (ESP).
The boot loader program in ESP is named
.Sy bootx64.efi
for AMD64 system and
.Sy bootia32.efi
for i386 system.
Note, only a 64-bit kernel is supported, even on i386 systems.
The
.Sy bootia32.efi
boot program is only provided to support systems with 32-bit UEFI firmware,
but which can support 64-bit mode.
.Pp
The
.Sy bootx64.efi
is copied from
.Sy /boot/loader64.efi
and
.Sy bootia32.efi
is copied from
.Sy /boot/loader32.efi .
.Ss Options
The
.Nm
command accepts the following options:
.Bl -tag -width Ds
.It Fl b Ar boot_dir
Provide path to the directory, where loader boot programs are located.
.Nm
will automatically pick the needed programs and will install to the
specified disk device.
.It Fl h
Prints short usage message.
.It Fl m
Installs
.Sy stage1
on the master boot sector interactively.
You must use this option if OS is installed on an extended FDISK or an EFI/GPT
partition.
.It Fl f
Suppresses interaction when overwriting the master boot sector on x86.
Force update on SPARC.
.It Fl n
Dry run session.
Will not write to disk.
.It Fl F
On SPARC, specify file system type.
On x86, inhibit version check and enforce boot loader update.
.It Fl u Ar verstr
Specify custom version string.
Can be used to add version on non-versioned boot loader or change built in
version string.
.It Fl i
Print version string from installed boot loader or from indicated file.
.It Fl e
Print version string from installed boot loader without description.
.It Fl V
Print version string from installed boot loader with full description.
.It Fl M
Mirror boot loader from installed disk partition.
.El
.Ss Operands
The
.Nm
command accepts the following operands:
.Bl -tag -width Ds
.It Ar bootblk
The name of the SPARC boot loader code.
.It Ar stage1
The name of the loader stage 1 file.
.It Ar stage2
The name of the loader stage 2 file.
.It Ar raw-device
The name of the device onto which bootloader code is to be installed.
It must be a character device that is readable and writable and part of boot
pool.
.El
.Sh FILES
.Bl -tag -width Ds
.It Pa /boot
Directory where x86 loader files reside.
.It Pa /usr/platform/platform name/lib/fs
Directory where SPARC boot loader files reside.
.El
.Sh EXAMPLES
.Bl -tag -width Ds
.It Sy Example 1 No Installing zfs boot loader on SPARC disk slice
The following command installs zfs boot loader on SPARC system:
.Bd -literal
# installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk \e
  /dev/rdsk/c0t0d0s0
.Ed
.It Sy Example 2 No Installing boot loader on x86 system
The following command installs loader stage files and master boot record:
.Bd -literal
# installboot -m /boot/pmbr /boot/gptzfsboot /dev/rdsk/c0t0d0s0
.Ed
.El
.Sh INTERFACE STABILITY
.Sy Uncommitted
.Sh SEE ALSO
.Xr attributes 7 ,
.Xr boot 8 ,
.Xr bootadm 8 ,
.Xr fdisk 8 ,
.Xr fmthard 8 ,
.Xr format 8 ,
.Xr kernel 8
.Sh WARNINGS
Installing
.Sy stage1
on the master boot sector
.Po
.Fl m
option
.Pc
overrides any boot loader currently installed on the machine.
The system will always boot the current OS partition regardless of which fdisk
partition is active.
.Pp
If version string indicates the source boot loader might be more recent,
.Nm
will also verify md5 checksums to determine if update is really necessary.
If checksums match, the install will not be performed.