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INSTALLBOOT(8) System Manager's Manual (alpha) INSTALLBOOT(8)

installboot
install disk bootstrap software

installboot [
-nv
] boot bootxx rawdiskdevice

The installboot utility prepares a disk for bootstrapping.
The OpenBSD/alpha disk bootstrap software is split into two parts: a small first-stage boot program that is written into the disklabel area of a disk (and hence is limited in size to 7680 bytes), and a second-stage boot program that resides in the filesystem proper (typically with the name /boot). The first-stage boot program is loaded into memory by the SRM console software. After receiving control of the system, it loads the second-stage boot program from a set of filesystem block numbers that have been hard-coded into it by installboot. The second-stage boot program locates and loads the kernel.
The second-stage boot program and the prototype code for the first-stage boot program can be found in /usr/mdec/boot and /usr/mdec/bootxx, respectively. /usr/mdec/boot may be installed simply by copying it to the root directory of the partition you wish to boot from, but after it is installed installboot must be run.
The options recognized by installboot are as follows:
 
 
Do not actually write anything on the disk.
 
 
Verbose mode.
The arguments are:
 
 
boot
The name of the second-stage boot program in the file system where the first-stage boot program is to be installed.
 
 
bootxx
The name of the prototype file for the first-stage boot program.
 
 
rawdiskdevice
The name of the device corresponding to the raw whole-disk partition (the “raw partition”) of the disk on which the first-stage boot program is to be installed.

boot resides in the FFS file system mounted on / from “sd0a”, you would install the first-stage boot program on the disk (and therefore make the disk bootable) by using the command:
# cp /usr/mdec/boot /boot 
# /usr/mdec/installboot -n -v /boot /usr/mdec/bootxx /dev/rsd0c
And if the information supplied looks right, run the above without the -n flag.

disklabel(8), init(8), sysctl(8)

The alpha installboot command first appeared in NetBSD 1.2.

The OpenBSD/alpha boot blocks can only load kernels from disks' “a” partitions. (However, the second-stage boot program may be located on any FFS file system partition on the disk.)
March 6, 2010 OpenBSD-6.1