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>
SEE ALSO
Etherboot tutorial at "http://etherboot.sourceforge.net/" Mtools
package is at "http://wauug.erols.com/pub/knaff/mtools/" Make sure you
have a recent version, the ability to map a drive to a file is not
present in old versions.
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.