.\" $NetBSD: installboot.8,v 1.92.4.1 2017/08/30 15:45:04 martin Exp $ .\" .\" Copyright (c) 2002-2017 The NetBSD Foundation, Inc. .\" All rights reserved. .\" .\" This code is derived from software contributed to The NetBSD Foundation .\" by Luke Mewburn of Wasabi Systems. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS .\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED .\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS .\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS .\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN .\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE .\" POSSIBILITY OF SUCH DAMAGE. .\" .Dd March 14, 2017 .Dt INSTALLBOOT 8 .Os .Sh NAME .Nm installboot .Nd install disk bootstrap software . .Sh SYNOPSIS .Nm .Op Fl fnv .Op Fl B Ar s2bno .Op Fl b Ar s1bno .Op Fl m Ar machine .Op Fl o Ar options .Op Fl t Ar fstype .Ar filesystem .Ar primary .Op Ar secondary .Nm .Fl c .Op Fl fnv .Op Fl m Ar machine .Op Fl o Ar options .Op Fl t Ar fstype .Ar filesystem .Nm .Fl e .Op Fl fnv .Op Fl m Ar machine .Op Fl o Ar options .Ar bootstrap . .Sh DESCRIPTION The .Nm utility installs and removes .Nx disk bootstrap software into a file system. .Nm can install .Ar primary into .Ar filesystem , or disable an existing bootstrap in .Ar filesystem . .Pp On some architectures the options of an existing installed bootstrap, or those of a bootstrap file can be changed. Installing a new primary bootstrap will reset those options to default values. .Pp Generally, .Nx disk bootstrap software consists of two parts: a .Dq primary bootstrap program usually written into the disklabel area of the file system by .Nm , and a .Dq secondary bootstrap program that usually resides as an ordinary file in the file system. .Pp When booting, the primary bootstrap program is loaded and invoked by the machine's PROM or BIOS. After receiving control of the system it loads and runs the secondary bootstrap program, which in turn loads and runs the kernel. The secondary bootstrap may allow control over various boot parameters passed to the kernel. .Pp Perform the following steps to make a file system bootable: .Bl -enum .It Copy the secondary bootstrap (usually .Pa /usr/mdec/boot. Ns Sy MACHINE or .Pa /usr/mdec/boot ) to the root directory of the target file system. . .It Use .Nm to install the primary bootstrap program (usually .Pa /usr/mdec/bootxx_ Ns Sy FSTYPE ) into .Ar filesystem . .Pp The following platforms do not require this step if the primary bootstrap already exists and the secondary bootstrap file is just being updated: .Sy alpha , .Sy amd64 , .Sy amiga , .Sy i386 , .Sy pmax , .Sy sparc64 , and .Sy vax . .Pp The following platform does not require the first step since a single bootstrap file is used. The single bootstrap is installed like the primary bootstrap on other platforms: .Sy next68k . .El .Pp The options and arguments recognized by .Nm are as follows: . .Bl -tag -width "optionsxxx" . .It Fl B Ar s2bno When hard-coding the blocks of .Ar secondary into .Ar primary , start from block .Ar s2bno instead of trying to determine the block numbers occupied by .Ar secondary by examining .Ar filesystem . If this option is supplied, .Ar secondary should refer to an actual secondary bootstrap (rather than the file name of the one present in .Ar filesystem ) so that its size can be determined. . .It Fl b Ar s1bno Install .Ar primary at block number .Ar s1bno instead of the default location for the machine and file system type. .Sy [ alpha , .Sy i386/amd64 (bootxx_fat16 only) , .Sy pmax , .Sy vax ] . .It Fl c Clear (remove) any existing bootstrap instead of installing one. . .It Fl e Edit the options of an existing bootstrap. This can be used to change the options in bootxx_xxxfs files, raw disk partitions, and the .Pa pxeboot_ia32.bin file. With .Fl v and without .Fl o , show the current options. .Sy [ amd64 , i386 ] . .It Fl f Forces .Nm to ignore some errors. . .It Fl m Ar machine Use .Ar machine as the target machine type. The default machine is determined from .Xr uname 3 and then .Ev MACHINE . The following machines are currently supported by .Nm : .Bd -ragged -offset indent .Sy alpha , .Sy amd64 , .Sy amiga , .Sy ews4800mips , .Sy hp300 , .Sy hppa , .Sy i386 , .Sy landisk , .Sy macppc , .Sy news68k , .Sy newsmips , .Sy next68k , .Sy pmax , .Sy sparc , .Sy sparc64 , .Sy sun2 , .Sy sun3 , .Sy vax , .Sy x68k .Ed . . .It Fl n Do not write to .Ar filesystem . . .It Fl o Ar options Machine specific .Nm options, comma separated. .Pp Supported options are (with the machines for they are valid in brackets): . .Bl -tag -offset indent -width alphasum . .It Sy alphasum .Sy [ alpha ] Recalculate and restore the Alpha checksum. This is the default for .Nx Ns Tn /alpha . . .It Sy append .Sy [ alpha , .Sy pmax , .Sy vax ] Append .Ar primary to the end of .Ar filesystem , which must be a regular file in this case. . .It Sy bootconf .Sy [ amd64 , .Sy i386 ] (Don't) read a .Dq boot.cfg file. . .It Sy command=\*[Lt]boot command\*[Gt] .Sy [ amiga ] Modify the default boot command line. . .It Sy console=\*[Lt]console name\*[Gt] .Sy [ amd64 , .Sy i386 ] Set the console device, \*[Lt]console name\*[Gt] must be one of: pc, com0, com1, com2, com3, com0kbd, com1kbd, com2kbd, com3kbd or auto. . .It Sy ioaddr=\*[Lt]ioaddr\*[Gt] .Sy [ amd64 , .Sy i386 ] Set the IO address to be used for the console serial port. Defaults to the IO address used by the system BIOS for the specified port. . .It Sy keymap=\*[Lt]keymap\*[Gt] .Sy [ amd64 , .Sy i386 ] Set a boot time keyboard translation map. Each character in \*[Lt]keymap\*[Gt] will be replaced by the one following it. For example, an argument of .Dq zyz would swap the lowercase letters .Sq y and .Sq z . . .It Sy modules .Sy [ amd64 , .Sy i386 ] (Don't) load kernel modules. . .It Sy password=\*[Lt]password\*[Gt] .Sy [ amd64 , .Sy i386 ] Set the password which must be entered before the boot menu can be accessed. . .It Sy resetvideo .Sy [ amd64 , .Sy i386 ] Reset the video before booting. . .It Sy speed=\*[Lt]baud rate\*[Gt] .Sy [ amd64 , .Sy i386 ] Set the baud rate for the serial console. If a value of zero is specified, then the current baud rate (set by the BIOS) will be used. . .It Sy sunsum .Sy [ alpha , .Sy pmax , .Sy vax ] Recalculate and restore the Sun and .Nx Ns Tn /sparc compatible checksum. .Em Note : The existing .Nx Ns Tn /sparc disklabel should use no more than 4 partitions. . .It Sy timeout=\*[Lt]seconds\*[Gt] .Sy [ amd64 , .Sy i386 ] Set the timeout before the automatic boot begins to the given number of seconds. .El . .It Fl t Ar fstype Use .Ar fstype as the type of .Ar filesystem . The default operation is to attempt to auto-detect this setting. The following file system types are currently supported by .Nm : . .Bl -tag -offset indent -width raid . .It Sy ffs .Bx Fast File System. . .It Sy raid Mirrored RAIDframe File System. . .It Sy raw .Sq Raw image. Note: if a platform needs to hard-code the block offset of the secondary bootstrap, it cannot be searched for on this file system type, and must be provided with .Fl B Ar s2bno . .El . .It Fl v Verbose operation. . .It Ar filesystem The path name of the device or file system image that .Nm is to operate on. It is not necessary for .Ar filesystem to be a currently mounted file system. . .It Ar primary The path name of the .Dq primary boot block to install. The path name must refer to a file in a file system that is currently mounted. . .It Ar secondary The path name of the .Dq secondary boot block, relative to the root of the file system in the device or image specified by the .Ar filesystem argument. Note that this may refer to a file in a file system that is not mounted. Most systems require .Ar secondary to be in the .Dq root directory of the file system, so the leading .Dq Pa / is not necessary on .Ar secondary . .Pp Only certain combinations of platform .Pq Fl m Ar machine and file system type .Pq Fl t Ar fstype require that the name of the secondary bootstrap is supplied as .Ar secondary , so that information such as the disk block numbers occupied by the secondary bootstrap can be stored in the primary bootstrap. These are: .Bl -column "Platform" "File systems" -offset indent .It Sy "Platform" Ta Sy "File systems" .It macppc Ta ffs, raw .It news68k Ta ffs, raw .It newsmips Ta ffs, raw .It sparc Ta ffs, raid, raw .It sun2 Ta ffs, raw .It sun3 Ta ffs, raw .El .El .Pp .Nm exits 0 on success, and \*[Gt]0 if an error occurs. . .Sh ENVIRONMENT .Nm uses the following environment variables: . .Bl -tag -width "MACHINE" . .It Ev MACHINE Default value for .Ar machine , overriding the result from .Xr uname 3 . . .El . .Sh FILES Most .Nx ports will contain variations of the following files: .Bl -tag -width /usr/mdec/bootxx_ustarfs . .It Pa /usr/mdec/bootxx_ Ns Sy FSTYPE Primary bootstrap for file system type .Sy FSTYPE . Installed into the bootstrap area of the file system by .Nm . . .It Pa /usr/mdec/bootxx_fat16 Primary bootstrap for .Tn MS-DOS .Sy FAT16 file systems. This differs from .Nm bootxx_msdos in that it doesn't require the filesystem to have been initialised with any .Ql reserved sectors . It also uses the information in the .Ql Boot Parameter Block to get the media and filesytem properties. The .Ql hidden sectors field of the BPB must be the offset of the partition in the disk. This can be set using the .Fl b Ar s1bno option. . .It Pa /usr/mdec/bootxx_ffsv1 Primary bootstrap for .Sy FFSv1 file systems (the .Ql traditional file system prior to .Nx 6.0 ) . Use .Xr dumpfs 8 to confirm the file system format is .Sy FFSv1 . . .It Pa /usr/mdec/bootxx_ffsv2 Primary bootstrap for .Sy FFSv2 file systems (the default file system for some platforms as of .Nx 6.0 ) . Use .Xr dumpfs 8 to confirm the file system format is .Sy FFSv2 . . .It Pa /usr/mdec/bootxx_lfsv1 Primary bootstrap for .Sy LFSv1 file systems. . .It Pa /usr/mdec/bootxx_lfsv2 Primary bootstrap for .Sy LFSv2 file systems (the default LFS version). . .It Pa /usr/mdec/bootxx_msdos Primary bootstrap for .Tn MS-DOS .Sy FAT file systems. . .It Pa /usr/mdec/bootxx_ustarfs Primary bootstrap for .Sy TARFS boot images. This is used by various install media. . .It Pa /usr/mdec/boot. Ns Sy MACHINE Secondary bootstrap for machine type .Sy MACHINE . This should be installed into the file system before .Nm is run. . .It Pa /usr/mdec/boot Synonym for .Pa /usr/mdec/boot. Ns Sy MACHINE . .It Pa /boot. Ns Sy MACHINE Installed copy of secondary bootstrap for machine type .Sy MACHINE . . .It Pa /boot Installed copy of secondary bootstrap. Searched for by the primary bootstrap if .Pa /boot. Ns Sy MACHINE is not found. . .El . .Ss Nx Ns Tn /evbmips files . The .Nx Ns Tn /evbmips bootstrap files currently only apply to the SBMIPS kernels for the SiByte/Broadcom BCM1250 and BCM1480 CPUs. .Bl -tag -width /usr/mdec/sbmips/bootxx_cd9660 . .It Pa /usr/mdec/sbmips/boot .Nx Ns Tn /evbmips secondary bootstrap for .Sy FFSv1 , .Sy FFSv2 , .Sy LFSv1 , and .Sy LFSv2 . .It Pa /usr/mdec/sbmips/bootxx_cd9660 SBMIPS primary bootstrap for ISO 9660 file system. .It Pa /usr/mdec/sbmips/bootxx_ffs SBMIPS primary bootstrap for FFSv1 and FFSv2 file system. .It Pa /usr/mdec/sbmips/bootxx_lfs SBMIPS primary bootstrap for LFSv1 and LFSv2 file system. .It Pa /usr/mdec/sbmips/netboot SBMIPS primary bootstrap for network root. .Pp Note that .Nm does not currently support evbmips directly. . .El . .Ss Nx Ns Tn /hppa files . .Bl -tag -width /usr/mdec/bootxx_ustarfs . .It Pa /usr/mdec/xxboot .Nx Ns Tn /hppa primary bootstrap for .Sy FFSv1 , .Sy FFSv2 , .Sy LFSv1 , and .Sy LFSv2 . .It Pa /usr/mdec/cdboot .Nx Ns Tn /hppa primary bootstrap for ISO 9660 file system. .It Pa /usr/mdec/sdboot Synonym for .Pa /usr/mdec/xxboot . .El . .Ss Nx Ns Tn /macppc files . .Bl -tag -width /usr/mdec/bootxx_ustarfs . .It Pa /usr/mdec/bootxx .Nx Ns Tn /macppc primary bootstrap. . .It Pa /usr/mdec/ofwboot .Nx Ns Tn /macppc secondary bootstrap. . .It Pa /ofwboot Installed copy of .Nx Ns Tn /macppc secondary bootstrap. . .El . .Ss Nx Ns Tn /next68k files . .Bl -tag -width /usr/mdec/bootxx_ustarfs . .It Pa /usr/mdec/boot .Nx Ns Tn /next68k bootstrap. . .El . .Ss Nx Ns Tn /sparc64 files . .Bl -tag -width /usr/mdec/bootxx_ustarfs . .It Pa /usr/mdec/bootblk .Nx Ns Tn /sparc64 primary bootstrap. . .It Pa /usr/mdec/ofwboot .Nx Ns Tn /sparc64 secondary bootstrap. . .It Pa /ofwboot Installed copy of .Nx Ns Tn /sparc64 secondary bootstrap. . .El . .Sh EXAMPLES . .Ss common Verbosely install the Berkeley Fast File System primary bootstrap on to disk .Sq sd0 : .Dl Ic installboot -v /dev/rsd0c /usr/mdec/bootxx_ffs Note: the .Dq whole disk partition (c on some ports, d on others) is used here, since the a partition probably is already opened (mounted as .Pa / ) , so .Nm would not be able to access it. .Pp Remove the primary bootstrap from disk .Sq sd1 : .Dl Ic installboot -c /dev/rsd1c . .Ss Nx Ns Tn /amiga Modify the command line to change the default from "netbsd -ASn2" to "netbsd -S": .Dl Ic installboot -m amiga -o command="netbsd -S" /dev/rsd0a /usr/mdec/bootxx_ffs . .Ss Nx Ns Tn /ews4800mips Install the System V Boot File System primary bootstrap on to disk .Sq sd0 , with the secondary bootstrap .Sq Pa /boot already present in the SysVBFS partition on the disk: .Dl Ic installboot /dev/rsd0c /usr/mdec/bootxx_bfs . .Ss Nx Ns Tn /i386 and Nx Ns Tn /amd64 Install new boot blocks on an existing .Sy FFSv2 mounted root file system on .Sq wd0 , setting the timeout to five seconds, after copying a new secondary bootstrap: .Dl Ic cp /usr/mdec/boot /boot .Dl Ic installboot -v -o timeout=5 /dev/rwd0a /usr/mdec/bootxx_ffsv2 .Bd -ragged -offset indent-two -compact .Em Note : Pre .Nx 6.0 systems used .Sy FFSv1 file systems on these platforms; double check with .Xr dumpfs 8 to be sure to use the correct secondary bootstrap. .Ed .Pp Create a bootable CD-ROM with an ISO 9660 file system for an i386 system with a serial console: .Dl Ic mkdir cdrom .Dl Ic cp sys/arch/i386/compile/mykernel/netbsd cdrom/netbsd .Dl Ic cp /usr/mdec/boot cdrom/boot .Dl Ic cp /usr/mdec/bootxx_cd9660 bootxx .Dl Ic installboot -o console=com0,speed=19200 -m i386 -e bootxx .Dl Ic makefs -t cd9660 -o 'bootimage=i386;bootxx,no-emul-boot' boot.iso \ cdrom . .Pp Create a bootable floppy disk with an FFSv1 file system for a small custom kernel (note: bigger kernels needing multiple disks are handled with the ustarfs file system): .Dl Ic newfs -s 1440k /dev/rfd0a .Bd -ragged -offset indent-two -compact .Em Note : Ignore the warnings that .Xr newfs 8 displays; it can not write a disklabel, which is not a problem for a floppy disk. .Ed .Dl Ic mount /dev/fd0a /mnt .Dl Ic cp /usr/mdec/boot /mnt/boot .Dl Ic gzip -9 \*[Lt] sys/arch/i386/compile/mykernel/netbsd \*[Gt] /mnt/netbsd.gz .Dl Ic umount /mnt .Dl Ic installboot -v /dev/rfd0a /usr/mdec/bootxx_ffsv1 . .Pp Create a bootable FAT file system on .Sq wd1a , which should have the same offset and size as a FAT primary partition in the Master Boot Record (MBR): .Dl Ic newfs_msdos -r 16 /dev/rwd1a .Bd -ragged -offset indent-two -compact .Em Notes : The .Fl r Ar 16 is to reserve space for the primary bootstrap. .Xr newfs_msdos 8 will display an .Dq MBR type such as .Ql 1 , .Ql 4 , or .Ql 6 ; the MBR partition type of the appropriate primary partition should be changed to this value. .Ed .Dl Ic mount -t msdos /dev/wd1a /mnt .Dl Ic cp /usr/mdec/boot /mnt/boot .Dl Ic cp path/to/kernel /mnt/netbsd .Dl Ic umount /mnt .Dl Ic installboot -t raw /dev/rwd1a /usr/mdec/bootxx_msdos .Pp Make the existing FAT16 filesystem on .Sq sd0e bootable. This can be used to make USB memory bootable provided it has 512 byte sectors and that the manufacturer correctly initialised the file system. .Dl Ic mount -t msdos /dev/sd0e /mnt .Dl Ic cp /usr/mdec/boot /mnt/boot .Dl Ic cp path/to/kernel /mnt/netbsd .Dl Ic umount /mnt .Dl Ic installboot /dev/rsd0e /usr/mdec/bootxx_fat16 It may also be necessary to use .Nm fdisk to make the device itself bootable. . .Pp Switch the existing installed bootstrap to use a serial console without reinstalling or altering other options such as timeout. .Dl Ic installboot -e -o console=com0 /dev/rwd0a .Ss Nx Ns Tn /macppc Note the .Nm utility is only required for macppc machines with OpenFirmware version 2 to boot. OpenFirmware 3 cannot load bootblocks specified in the Apple partition map. .Pp Install the Berkeley Fast File System primary bootstrap on to disk .Sq wd0 : .Dl Ic installboot /dev/rwd0c /usr/mdec/bootxx /ofwboot .Pp The secondary .Nx Ns Tn /macppc bootstrap is located in .Pa /usr/mdec/ofwboot . .Pp The primary bootstrap requires the raw .Pa ofwboot for the secondary bootstrap, not .Pa ofwboot.xcf , which is used for the OpenFirmware to load kernels. .Ss Nx Ns Tn /next68k Install the bootstrap on to disk .Sq sd0 : .Dl Ic installboot /dev/rsd0c /usr/mdec/boot . .Ss Nx Ns Tn /pmax Install the Berkeley Fast File System primary bootstrap on to disk .Sq sd0 : .Dl Ic installboot /dev/rsd0c /usr/mdec/bootxx_ffs .Pp .Nx Ns Tn /pmax requires that this file system starts at block 0 of the disk. .Pp Install the ISO 9660 primary bootstrap in the file .Pa /tmp/cd-image : .Dl Ic installboot -m pmax /tmp/cd-image /usr/mdec/bootxx_cd9660 .Pp Make an ISO 9660 filesystem in the file .Pa /tmp/cd-image and install the ISO 9660 primary bootstrap in the filesystem, where the source directory for the ISO 9660 filesystem contains a kernel, the primary bootstrap .Pa bootxx_cd9660 and the secondary bootstrap .Pa boot.pmax : .Dl Ic mkisofs -o /tmp/cd-image -a -l -v iso-source-dir .Dl ... .Dl 48 51 iso-source-dir/bootxx_cd9660 .Dl ... .Dl Ic installboot -b `expr 48 \e* 4` /tmp/cd-image /usr/mdec/bootxx_cd9660 . .Ss Nx Ns Tn /sparc Install the Berkeley Fast File System primary bootstrap on to disk .Sq sd0 , with the secondary bootstrap .Sq Pa /boot already present: .Dl Ic installboot /dev/rsd0c /usr/mdec/bootxx /boot . .Ss Nx Ns Tn /sparc64 Install the primary bootstrap on to disk .Sq sd0 : .Dl Ic installboot /dev/rsd0c /usr/mdec/bootblk .Pp The secondary .Nx Ns Tn /sparc64 bootstrap is located in .Pa /usr/mdec/ofwboot . . .Ss Nx Ns Tn /sun2 and Nx Ns Tn /sun3 Install the Berkeley Fast File System primary bootstrap on to disk .Sq sd0 , with the secondary bootstrap .Sq Pa /boot already present: .Dl Ic installboot /dev/rsd0c /usr/mdec/bootxx /boot . .Sh SEE ALSO .Xr uname 3 , .Xr boot 8 , .Xr disklabel 8 , .Xr dumpfs 8 , .Xr fdisk 8 , .Xr pxeboot 8 . .Sh HISTORY This implementation of .Nm appeared in .Nx 1.6 . . .Sh AUTHORS .An -nosplit The machine independent portion of this implementation of .Nm was written by .An Luke Mewburn . The following people contributed to the various machine dependent back-ends: .An Simon Burge (pmax), .An Chris Demetriou (alpha), .An Matthew Fredette (sun2, sun3), .An Matthew Green (sparc64), .An Ross Harvey (alpha), .An Michael Hitch (amiga), .An Paul Kranenburg (sparc), .An David Laight (i386), .An Christian Limpach (next68k), .An Luke Mewburn (macppc), .An Matt Thomas (vax), .An Izumi Tsutsui (news68k, newsmips), and .An UCHIYAMA Yasushi (ews4800mips). . .Sh BUGS There are not currently primary bootstraps to support all file systems types which are capable of being the root file system. .Pp If a disk has been converted from .Sy FFS to .Sy RAID without the contents of the disk erased, then the original .Sy FFS installation may be auto-detected instead of the .Sy RAID installation. In this case, the .Fl t Ar raid option must be provided. . .Ss Nx Ns Tn /alpha The .Nx Ns Tn /alpha primary bootstrap program can only load the secondary bootstrap program from file systems starting at the beginning (block 0) of disks. Similarly, the secondary bootstrap program can only load kernels from file systems starting at the beginning of disks. .Pp The size of primary bootstrap programs is restricted to 7.5KB, even though some file systems (e.g., ISO 9660) are able to accommodate larger ones. . .Ss Nx Ns Tn /hp300 The disk must have a boot partition large enough to hold the bootstrap code. Currently the primary bootstrap must be a LIF format file. . .Ss Nx Ns Tn /i386 and Nx Ns Tn /amd64 The bootstrap must be installed in the .Nx partition that starts at the beginning of the mbr partition. If that is a valid filesystem and contains the .Pa /boot program then it will be used as the root filesystem, otherwise the .Sq a partition will be booted. .Pp The size of primary bootstrap programs is restricted to 8KB, even though some file systems (e.g., ISO 9660) are able to accommodate larger ones. . .Ss Nx Ns Tn /macppc Due to restrictions in .Nm and the secondary bootstrap implementation, file systems where kernels exist must start at the beginning of disks. .Pp Currently, .Nm doesn't recognize an existing Apple partition map on the disk and always writes a faked map to make disks bootable. .Pp The .Nx Ns Tn /macppc bootstrap program can't load kernels from .Sy FFSv2 partitions. .Ss Nx Ns Tn /next68k The size of bootstrap programs is restricted to the free space before the file system at the beginning of the disk minus 8KB. . .Ss Nx Ns Tn /pmax The .Nx Ns Tn /pmax secondary bootstrap program can only load kernels from file systems starting at the beginning of disks. .Pp The size of primary bootstrap programs is restricted to 7.5KB, even though some file systems (e.g., ISO 9660) are able to accommodate larger ones. . .Ss Nx Ns Tn /sun2 and Nx Ns Tn /sun3 The .Nx Ns Tn /sun2 and .Nx Ns Tn /sun3 secondary bootstrap program can only load kernels from file systems starting at the beginning of disks. . .Ss Nx Ns Tn /vax The .Nx Ns Tn /vax secondary bootstrap program can only load kernels from file systems starting at the beginning of disks. .Pp The size of primary bootstrap programs is restricted to 7.5KB, even though some file systems (e.g., ISO 9660) are able to accommodate larger ones.