INSTALLBOOT(8) Maintenance Commands and Procedures INSTALLBOOT(8)

installboot — install bootloader in a disk partition

installboot [-fn] [-F zfs||] [-u verstr] bootblk raw-device

installboot [-enV] -F zfs -i raw-device | file

installboot [-n] -F zfs -M raw-device attach-raw-device

installboot [-fFmn] [-b boot_dir] [-u verstr] [stage1 stage2] raw-device

installboot [-enV] -i raw-device | file

installboot [-n] -M raw-device attach-raw-device

The boot(8) boot program is loaded from disk and is responsible of loading kernel and its support files from specific file system.

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, installboot command will split the zfs boot loader between disk slice boot area, and zfs pool boot area.

The x86 BIOS systems have boot loader implemented as three stages:

/boot/pmbr is used as master boot record (MBR) and partition boot program.
/boot/gptzfsboot is responsible for loading files from file system. The stage2 on x86 systems is always installed to zfs pool boot area, and therefore only zfs boot is supported. installboot command will record the location of stage2 to stage1, which is always installed at least on partition (MBR or GPT) boot area, making it possible to boot via chainload from other boot loaders.

When installboot command is used with the -m option, installboot installs the stage1 file on the master boot sector of the disk as well.

/boot/loader is read from file system and executed by stage2 and will provide boot loader user environment and is responsible of loading and starting the operating system kernel.

In case of GPT partitioning scheme, if the file system to boot from is either UFS or PCFS, there must be partition defined to store stage2 boot program. This is needed because UFS and PCFS do not have sufficient space reserved to store boot programs.

The boot partition must use following GPT UUID:

6a82cb45-1dd2-11b2-99a6-080020736631

which is provided by "boot" tag in format(8) partition menu.

The x86 UEFI systems load and start boot loader program from directory of the EFI System Partition (ESP). The boot loader program in ESP is named bootx64.efi for AMD64 system and bootia32.efi for i386 system. Note, only a 64-bit kernel is supported, even on i386 systems. The bootia32.efi boot program is only provided to support systems with 32-bit UEFI firmware, but which can support 64-bit mode.

The bootx64.efi is copied from and bootia32.efi is copied from .

The installboot command accepts the following options:

boot_dir
Provide path to the directory, where loader boot programs are located. installboot will automatically pick the needed programs and will install to the specified disk device.
Prints short usage message.
Installs 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.
Suppresses interaction when overwriting the master boot sector on x86. Force update on SPARC.
Dry run session. Will not write to disk.
On SPARC, specify file system type. On x86, inhibit version check and enforce boot loader update.
verstr
Specify custom version string. Can be used to add version on non-versioned boot loader or change built in version string.
Print version string from installed boot loader or from indicated file.
Print version string from installed boot loader without description.
Print version string from installed boot loader with full description.
Mirror boot loader from installed disk partition.

The installboot command accepts the following operands:

bootblk
The name of the SPARC boot loader code.
stage1
The name of the loader stage 1 file.
stage2
The name of the loader stage 2 file.
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.

/boot
Directory where x86 loader files reside.
/usr/platform/platform name/lib/fs
Directory where SPARC boot loader files reside.

Installing zfs boot loader on SPARC disk slice
The following command installs zfs boot loader on SPARC system: 
# installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk \
  /dev/rdsk/c0t0d0s0
Installing boot loader on x86 system
The following command installs loader stage files and master boot record: 
# installboot -m /boot/pmbr /boot/gptzfsboot /dev/rdsk/c0t0d0s0

attributes(7), boot(8), bootadm(8), fdisk(8), fmthard(8), format(8), kernel(8)

Installing stage1 on the master boot sector (-m option) 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.

If version string indicates the source boot loader might be more recent, installboot will also verify md5 checksums to determine if update is really necessary. If checksums match, the install will not be performed.

October 16, 2021 OmniOS