Ubuntu Manpage: mknbi - make network bootable image

NAME

       mknbi - make network bootable image

SYNOPSIS

       mknbi --version

       mknbi --format=format --target=target [--output=outputfile] target-specific-arguments

       mkelf-linux [--output=outputfile] kernelimage [ramdisk]

       mknbi-linux [--output=outputfile] kernelimage [ramdisk]

       mknbi-rom [--output=outputfile] .z?rom-file

       mkelf-img [--output=outputfile] .z?img-file

       mkelf-menu [--output=outputfile] [dataimage]

       mknbi-menu [--output=outputfile] [dataimage]

       mkelf-nfl [--output=outputfile] [dataimage]

       mknbi-nfl [--output=outputfile] [dataimage]

       mkelf-lua [--output=outputfile] luabin

       mknbi-fdos [--output=outputfile] kernel.sys floppyimage

       mknbi-dos [--output=outputfile] floppyimage

DESCRIPTION

       mknbi is a program that makes network bootable images for various operating systems suitable for network
       loading by Etherboot or Netboot, which are ROM boot loaders.  If you are looking to boot using PXE, look
       no further, mknbi is not what you want. You probably want something like PXELINUX which is part of the
       SYSLINUX package.

       mknbi --version prints the current version. Use this before reporting problems.

       mknbi can be invoked with the --format and --target options or links can be made to it under format and
       target specific names. E.g.  mkelf-linux is the same as mknbi --format=elf --target=linux.

       --format=format Specify the format of the output. Currently available are nbi and elf.  ELF format only
       works with linux and menu.  Otherwise the invocation is the same as for mknbi. In discussions below, the
       mknbi form is used.

       --target=target Specify the target binary. Currently available are linux, menu, rom, fdos and dos. mknbi
       is not needed for booting FreeBSD.

       --output=outputfile Specify the output file, can be used with all variants.  Stdout is the default.

       The package must be installed in the destination location before the executables can be run, because it
       looks for library files.

       Each of the variants will be described separately.

MKELF-LINUX

       mkelf-linux and mknbi-linux makes a boot image from a Linux kernel image, either a zImage or a bzImage.

MKELF-LINUX OPTIONS

--param=string Replace the default parameter string with the specified one. This option overrides all the
following options so you should know what you are doing.

--append=string Appends the specified string to the existing parameter string. This option operates after
the other parameter options have been evaluated.

--rootdir=rootdir Define name of directory to mount via NFS from the boot server.

In the absence of this option, the default is to use the directory "/tftpboot/"%s, with the %s
representing the hostname or IP-address of the booting system, depending on whether the hostname
attribute is present in the BOOTP/DHCP reply.

If "rom" is given, and if the BOOTP/DHCP server is able to handle the RFC 1497 extensions, the value of
the rootpath option is used as the root directory.

If the name given to the option starts with "/dev/", the corresponding device is used as the root device,
and no NFS directory will be mounted.

--rootmode="ro|rw" Defines whether the root device will be mounted read-only or read-write respectively.
Without this parameter, the default is "rw".

--ip=string Define client and server IP addresses.

In the absence of this option no IP addresses are defined, and the kernel will determine the IP addresses
by itself, usually by using DHCP, BOOTP or RARP. Note that the kernel's query is in addition to the
query made by the bootrom, and requires the IP: kernel level autoconfiguration (CONFIG_IP_PNP) feature to
be included in the kernel.

Important note: In Linux kernels 2.2.x where x >= 18, and 2.4.x where x >= 5, it is necessary to specify
one of the enabling options in the next paragraph to cause the IP autoconfiguration to be activated.
Unlike in previous kernels, IP autoconfiguration does not happen by default. Also note that IP
autoconfiguration and NFSroot are likely to go away in Linux 2.6 and that userspace IP configuration
methods using ramdisk and userspace DHCP daemons are preferred now.

If one of the following: "off, none, on, any, dhcp, bootp, rarp, both", is given, then the option will be
passed unmodified to the kernel and cause that autoconfig option to be chosen.

If "rom" is given as the argument to this option, all necessary IP addresses for NFS root mounting will
be inherited from the BOOTP/DHCP answer the bootrom got from the server.

It's also possible to define the addresses during compilation of the boot image. Then, all addresses must
be separated by a colon, and ordered in the following way:

"--ip="client:server:gateway:netmask:hostname[:dev[:proto]]

Using this option mkelf-linux will automatically convert system names into decimal IP addresses for the
first three entries in this string. The hostname entry will be used by the kernel to set the host name
of the booted Linux diskless client. When more than one network interface is installed in the diskless
client, it is possible to specify the name of the interface to use for mounting the root directory via
NFS by giving the optional value "dev". This entry has to start with the string "eth" followed by a
number from 0 to 9. However, if only one interface is installed in the client, this dev entry including
the preceding semicolon can be left out. The proto argument is one of the IP autoconfiguration enabling
options listed above. (Author: it's not clear to me what the IP autoconfiguration does when the
parameters are already specified. Perhaps it's to obtain parameters not specified, e.g. NIS domain.)

--rdbase=top|asis|0xNNNNNNNN Set the ramdisk load address. "top" moves the ramdisk to the top of memory
before jumping to the kernel. This is the default if rdbase is not specified. This option requires that
first-linux's kernel sizing work correctly. "asis" loads it at 0x100000 (1MB) if the kernel is loaded
low; or leaves it just after the kernel in memory, if the kernel is loaded high. For this option to work,
the kernel must be able to handle ramdisks at these addresses. 0xNNNNNNNN moves the ramdisk to the hex
address specified. The onus is on the user to specify a suitable address that is acceptable to the kernel
and doesn't overlap with any other segments. Etherboot will round address down to multiple of 4k (last 3
digits to zero).

--rdnopad By default, etherboot pads (with nulls) the given initrd of any size to multiple of 4k bytes
(aligning to memory page boundary). Use this option to disable padding if it causes problem.

--first32=program Override the default first stage setup program. It can be used to call extensions to
the Etherboot code, which paves the way for additional useful functionality without enlarging the size of
the Etherboot footprint. --first32 is implied by the ELF format.

--progreturns This option is used in conjunction with and only valid with the --first32 option to
indicate to the Etherboot loader that the called program will return to loader and hence Etherboot should
not disable the network device as is the case when the program will never return to Etherboot.

--relocseg=segaddr This option is used to specify a relocation of the Linux first, boot, setup, and
parameter segments to another 64k band. Currently the only valid values are 0x9000 and 0x8000,
corresponding to linear addresses of 0x90000 and 0x80000 upwards. The default is 0x9000. Usually you use
this option if you have relocated Etherboot to 0x84000 to avoid other code in the 0x90000 segment like
DOC. The Linux kernel must support relocation which implies a 2.4 kernel or later. --relocseg only works
reliably with ELF or --first32=.

mem=memsize This is not a command line option but a kernel parameter that is intercepted by the first32
stage and used as the top of memory, to match Linux's interpretation. memsize can be suffixed by "G" to
indicate gibibytes (times 2^30), "M" to indicate mebibytes (times 2^20) or "K" to indicate kibibytes
(times 2^10). Note that the suffixes are uppercase. This kernel parameter can be specified in --append=
or option-129 of the DHCP/BOOTP record.

Run the program thus:

mkelf-linux kernel-image [ramdisk-image] > linux.nb

Then move linux.nb to where the network booting process expects to find it.

MKELF-LINUX BOOTP/DHCP VENDOR TAGS

mkelf-linux includes a startup code at the beginning of the Linux kernel which is able to detect certain
DHCP vendor defined options. These can be used to modify the kernel loading process at runtime. To use
these options with ISC DHCPD v3, a popular DHCP daemon, the syntax is as below. You will need to adjust
the syntax for other DHCP or BOOTP daemons.

option etherboot-signature code 128 = string;

option kernel-parameters code 129 = text;

...

option etherboot-signature E4:45:74:68:00:00;

option kernel-parameters "INITRD_DBG=6 NIC=3c509";

Option 128 is required to be the six byte signature above. See the vendortags appendix of the Etherboot
user manual for details.

The following option is presently supported by mkelf-linux:

129 The string value given with this option is appended verbatim to the end of the kernel command line.
It can be used to specify arguments like I/O addresses or DMA channels required for special hardware like
SCSI adapters, network cards etc. Please consult the Linux kernel documentation about the syntax required
by those options. It is the same as the --append command line option to mkelf-linux, but works at boot
time instead of image build time.

130 With this option it is possible to the select the network adapter used for mounting root via NFS on a
multihomed diskless client. The syntax for the string value is the same as for the "dev" entry used with
the --ip= option as described above. However note that the mkelf-linux runtime setup routine does not
check the syntax of the string.

MKNBI-ROM

       mknbi-rom makes a boot image from an Etherboot ".rom" or ".zrom" boot ROM image.  This allows it to be
       netbooted using an existing ROM. This is useful for developing Etherboot drivers or to load a newer
       version of Etherboot with an older one.

       Run mknbi-rom like this:

       mknbi-rom nic.zrom > nic.nb

       Move nic.nb to where the network booting process expects to find it.  The boot ROM will load this as the
       operating system and execute the ROM image.

MKELF-IMG

       mkelf-img makes a boot image from an Etherboot ".img" or ".zimg" image.  This allows it to be netbooted
       using an existing ROM. This is useful for developing Etherboot drivers or to load a newer version of
       Etherboot with an older one.

       Run mkelf-img like this:

       mkelf-img nic.zimg > nic.nb

       Move nic.nb to where the network booting process expects to find it.  The boot ROM will load this as the
       operating system and execute the image.

       Note that this does not test the ROM loader portion that's in a ".z?rom" image, but not in a ".z?img".

MKELF-MENU

mkelf-menu and mknbi-menu make a boot image from an auxiliary menu program. Etherboot has the ability to
load an auxiliary program which can interact with the user, modify the DHCP structure, and return a
status. Based on the status, Etherboot can load another binary, restart or exit. This makes it possible
to have elaborate user interface programs without having to modify Etherboot. The specification for
auxiliary program is documented in the Etherboot Developer's Manual.

mkelf-menu and mknbi-menu take a binary named "menu" from the library directory, which is assumed to have
an entry point of 0x60000. An optional argument is accepted, and this is loaded at 0x80000. This can be
a data file used by the menu program.

Currently, the menu binary provided duplicates the builtin menu facility of Etherboot with the exception
of a couple of small differences: no server or gateway specifications are used and nested TFTP loads
don't work. You should not have MOTD or IMAGE_MENU defined in your Etherboot build to be able to use this
external menu binary. The specifications of the DHCP option required is in the vendortags document in the
Etherboot user manual.

Typical usage is like this:

mkelf-menu > menu.nb

Then put menu.nb in the TFTP boot directory and edit your DHCP options according to the documentation.

Alternate user interface programs are highly encouraged.

MKELF-NFL

       mkelf-nfl and mknbi-nfl make a boot image from the NFL menu program. This menu program takes the names of
       images from a menu-text-file file which just contains lines with the filenames (relative to the tftpd
       root directory) of images to load. The user-interface is a light-bar, similar to that used in GRUB.
       There is a sample menu-text-file in "menu-nfl.eg". The special entry "Quit Etherboot" (without quotes, of
       course) can be used in menu-text-files as an entry that causes Etherboot to quit and return to the
       invoking environment, which is the BIOS in the case of ROMs.

       Typical usage is:

       mkelf-nfl menu-text-file > nfl.nb

       Then put nfl.nb in the TFTP boot directory and specify as the boot image. Chaining to other menus works.

       Enhancements to the menu format accepted to specify other features such as titles, timeout, colours, and
       so forth are highly encouraged.

MKELF-LUA

       mkelf-lua makes an ELF image from a precompiled Lua ("http://www.tecgraf.puc-rio.br/lua/") program.

       Typical usage is:

       mkelf-lua hello.lb > luaprog.nb

       where "hello.lb" was generated from a Lua program by:

       luac -o hello.lb hello.lua

       The functions available to Lua programs in this environment is described in a separate document.

MKNBI-FDOS

mknbi-fdos makes a boot image from a FreeDOS kernel file and a floppy image. Note that the kernel image
is not read from the floppy section of the boot image, but is a separate section in the boot image. The
bootloader has been adjusted to jump to it directly. This means the space that would be taken up on the
floppy by the kernel image file can now be used for applications and data.

Obtain a distribution of FreeDOS with a recent kernel, probably at least 2006. It has been tested with
2012 but nothing older. You can get the FreeDOS kernel here:

"http://freedos.sourceforge.net/"

Follow the instructions to make a bootable floppy. Then get an image of the floppy with:

dd if=/dev/fd0 of=/tmp/floppyimage

Also extract kernel.sys from the floppy. You can do this from the image using the mtools package, by
specifying a file as a drive with a declaration like this in ~/.mtoolsrc:

drive x: file="/tmp/floppyimage"

Then run:

mcopy x:kernel.sys .

Then run mknbi by:

mknbi-fdos kernel.sys /tmp/floppyimage > freedos.nb

where kernel.sys and /tmp/floppyimage are the files extracted above. Then move freedos.nb to where the
network booting process expects to find it.

If you have got it to netboot successfully, then you can go back and add your files to the floppy image.
You can delete kernel.sys in the floppy image to save space, that is not needed. Note that you can create
a floppy image of any size you desire with the mformat program from mtools, you are not restricted to the
actual size of the boot floppy.

MKNBI-FDOS OPTIONS

       --harddisk Make the boot ramdisk the first hard disk, i.e. C:. One reason you might want to do this is
       because you want to use the real floppy. The limit on "disk size" in the boot image is not raised by this
       option so that is not a reason to use this option. This option is incompatible with --disableharddisk.

       --disableharddisk When the ramdisk is simulating a floppy disk drive, this switch will disable hard disk
       accesses.  This is necessary if the client should use a network file system as drive C:, which is only
       possible if there are no hard disks found by DOS. This option is incompatible with --harddisk.

       --nosquash Do not try to chop unused sectors from the end of the floppy image. This increases the boot
       image size and hence loading time if the FAT filesystem on the floppy is mostly empty but you may wish to
       use this option if you have doubts as to whether the squashing algorithm is working correctly.

       --rdbase=0xNNNNNNNN Set the ramdisk load address. The default load address for the ramdisk is 0x110000.
       It can be moved higher (lower will not work) if for some reason you need to load other stuff at the
       address it currently occupies. As this is a linear address and not a segment address, the last 4 bits are
       not used and should be 0.

MKNBI-DOS

mknbi-dos makes a boot image from a floppy image containing a bootable DOS filesystem. It is not
necessary to build the filesystem on a physical floppy if you have the mtools package, but you need a
bootable floppy of any size to start with. First extract the boot block from the floppy, this boot block
must match the DOS kernel files you will copy in the next step:

dd if=/dev/fd0 of=bootblock bs=512 count=1

Then get the DOS kernel files (this is correct for DR-DOS, the names are different in MS-DOS, IO.SYS and
MSDOS.SYS):

mcopy a:IBMBIO.COM a:IBMDOS.COM a:COMMAND.COM .

Next make an entry in ~/.mtoolsrc to declare a floppy to be mapped to a file:

drive x: file="/tmp/floppyimage"

Now format a floppy of the desired size, in this example a 2.88 MB floppy, at the same time writing the
bootblock onto it:

mformat -C -t 80 -s 36 -h 2 -B bootblock x:

The size of the "floppy" is only limited by the limits on the number of cylinders, sectors and heads,
which are 1023, 63 and 255 respectively, and the amount of RAM you are willing to allocate to the
"floppy" in memory. As RAM is precious, choose a size slightly bigger than what is needed to hold your
"floppy" files.

Finally, copy all your desired files onto the floppy:

mcopy IBMBIO.COM x:

mcopy IBMDOS.COM x:

mcopy COMMAND.COM x:

mcopy CONFIG.SYS AUTOEXEC.BAT APP.EXE APP.DAT ... x:

For MS-DOS substitute IO.SYS for IBMIO.COM, and MSDOS.SYS for IBMDOS.COM. The case of the files must be
preserved, it may not work if VFAT lower case names are generated in the floppy image. Pay attention to
the order of copying as the boot block may expect the first two entries on a newly formatted disk to be
IO.SYS, MSDOS.SYS. Possibly too COMMAND.COM has to be the third entry so we play safe. Thanks to Phil
Davey and Phillip Roa for these tips.

I have reports that the bootblock of MS-DOS 6.22 sometimes fails to boot the ramdisk. You could try
using the boot block from Netboot instead of getting the boot block off the floppy. I have provided this
boot block in the distribution as altboot.bin, and in source form as altboot.S and boot.inc. One
essential thing is to make IO.SYS the first file on the disk, or this bootblock will not work.

If you happen to have a media of the same size you could test if the image is bootable by copying it onto
the media, and then booting it:

dd if=/tmp/floppyimage of=/dev/fd0

Then run mknbi-dos over the image /tmp/floppyimage to create a boot image:

mknbi-dos /tmp/floppyimage > dos.nb

Move dos.nb to where the network booting process expects to find it.

MKNBI-DOS OPTIONS

       --harddisk Make the boot ramdisk the first hard disk, i.e. C:. One reason you might want to do this is
       because you want to use the real floppy. The limit on "disk size" in the boot image is not raised by this
       option so that is not a reason to use this option. This option is incompatible with --disableharddisk.

       --disableharddisk When the ramdisk is simulating a floppy disk drive, this switch will disable hard disk
       accesses.  This is necessary if the client should use a network file system as drive C:, which is only
       possible if there are no hard disks found by DOS. This option is incompatible with --harddisk.

       --nosquash Do not try to chop unused sectors from the end of the floppy image. This increases the boot
       image size and hence loading time if the FAT filesystem on the floppy is mostly empty but you may wish to
       use this option if you have doubts as to whether the squashing algorithm is working correctly.

       --rdbase=0xNNNNNNNN Set the ramdisk load address. The default load address for the ramdisk is 0x110000.
       It can be moved higher (lower will not work) if for some reason you need to load other stuff at the
       address it currently occupies. As this is a linear address and not a segment address, the last 4 bits are
       not used and should be 0.

BUGS

       Please report all bugs to Etherboot users mailing list: <https://sourceforge.net/mail/?group_id=4233>

COPYRIGHT

       mknbi is under the GNU Public License

AUTHOR

       Ken Yap

       mk{elf,nbi}-nfl was contributed by Robb Main of Genedyne.

DATE

       See man page footer for date and version. Sorry, not available in the HTML version.