OFWBOOT(8) System Manager's Manual (MacPPC) OFWBOOT(8)

NAME

ofwboot, ofwboot.elf, ofwboot.xcf — Open Firmware boot command

SYNOPSIS

ofwboot

DESCRIPTION

Open Firmware is a FORTH-like command interpreter started by the BootROM after the power-on self test (POST). This command interpreter allows the user flexibility in choosing how their machine boots an operating system. NetBSD uses Open Firmware to initialize many of the devices in a system and uses it to load the primary bootloader, ofwboot.

The information in this man page should only serve as a guideline for users. Apple has made many revisions to Open Firmware, and the earlier versions had many problems and inconsistencies. You may find that a boot command that works on one model will not work on another.

In this man page, only one Open Firmware command will be described, boot, because it is used to pass arguments to ofwboot. The Open Firmware boot command takes up to three arguments:

boot [boot-device [boot-file]] [options]

boot-device
primary bootloader location
boot-file
kernel location
options
flags passed to the kernel (see below)

boot-device

The first argument, boot-device, actually designates the primary bootloader location and its name in the form:
boot-device:[partition-num],[bootloader-filename]
A typical example, from a PowerBook (FireWire), is
/pci@f2000000/mac-io@17/ata-4@1f000/@0:9,ofwboot.xcf
Note that colon (`:') delimits the device to the left, and comma (`,') separates the boot loader filename from the first part. For Open Firmware versions before 3, the primary bootloader is installed in partition “zero”, and it is not necessary to specify the bootloader-filename. For Open Firmware version 3, you must specify the bootloader-filename.

Open Firmware stores aliases to common devices in NVRAM. In the example above, /pci@f2000000/mac-io@17/ata-4@1f000/@0 is the path on a PowerBook (FireWire) to the built-in ATA/100 hard drive. Use the devalias command in Open Firmware to print out a list of common device names on a particular model. The command above could then be simplified to:

hd:9,ofwboot.xcf

boot-loader-file-name is usually ofwboot.xcf. (See also the FILES section for further discussion.)

If omitted, the Open Firmware variable boot-device is used.

boot-file

It may be necessary to specify the boot-file if Open Firmware does not know where to find the kernel. The default is to load the file named netbsd on partition “a” from the device used to load the primary bootloader.

For systems with Open Firmware versions less than 3 which are set up using sysinst, the boot-file argument is not necessary. Systems with Open Firmware version 3 may need to specify the boot-file.

The syntax is similar to the boot-device argument:

[boot-file-device:partition-num/][kernel-name]
This is a little different, since a kernel-name may be specified without listing a boot-file-device and partition-num. Additionally, a boot-file-device and partition-num may need to be specified, while using the default kernel-name.

If no kernel-name is specified, the primary bootloader will try to find kernels named either netbsd or netbsd.gz on the boot-device or (if specified) boot-file-device.

options

Possible options are:
-a
ask for the boot device
-s
single-user mode boot
-d
debug mode
exit
exit to Open Firmware after processing arguments

ENVIRONMENT

If set, the following Open Firmware variables will be used to determine which boot-device and boot-file Open Firmware should use when booting a system. If the user specifies arguments on the command line, these values are overridden.
boot-device
used as the first argument
boot-file
used as the second argument
auto-boot?
setting this variable to false will present the user with an Open Firmware command prompt after power-on reset. A value of true will automatically boot the system using the variables boot-device and boot-file. (This is not really related to the boot command, but is included for completeness.)
To restore these variables to their default values, use the set-default Open Firmware command: set-default boot-device

FILES

The three files ofwboot, ofwboot.elf, and ofwboot.xcf are the same program, in different executable formats.
ofwboot
ofwboot is installed via installboot(8) on systems with Open Firmware versions less than 3. It is not necessary to specify this file name, as it is stored in a special location on the disk, partition “zero”. For example, the following command might be used to boot from a SCSI device with ID 2: 0 >boot scsi-int/sd@2:0.
ofwboot.xcf
ofwboot.xcf is in XCOFF format. This file is used on all Open Firmware 3 systems, and on Open Firmware systems prior to 3 when the bootloader is not installed in partition “zero”, such as from an ISO-9660 format CD-ROM.
ofwboot.elf
ofwboot.elf is in elf(5) format and only functions on systems with Open Firmware version 3. To avoid confusion, all users should be using ofwboot.xcf, as ofwboot.elf offers no additional functionality. It is only included for historical reasons.
boot.fs
This 1.44 MB disk image contains everything necessary to boot and install NetBSD. It includes the partition “zero” bootloader (ofwboot), an INSTALL kernel (with limited device drivers), and the sysinst utility in a RAM disk. Since Open Firmware does not care what media files are loaded from, only whether they are supported and in the correct format, this disk image may be placed on media other than floppy disks, such as hard drives or Zip disks. Use dd(1) on Unix, or DiskCopy on MacOS 9.1 or later, or suntar on any MacOS version to copy this image onto the media.
netbsd
production kernel, using the GENERIC set of devices which supports almost all hardware available for this platform.
netbsd_GENERIC_MD.gz
GENERIC kernel (the same as netbsd), with RAM disk and sysinst included.
macppccd.iso
bootable CDROM image for all supported systems. Usually located at ftp://ftp.NetBSD.org/pub/NetBSD/iso/{RELEASE}/macppccd.iso

EXAMPLES

ERRORS

DEFAULT CATCH!, code=FF00300 at %SRR0: FF80AD38 %SRR1: 00001070
Could be “device not found” or I/O errors on the device. The numbers are just for example.

Can't LOAD from this device
Open Firmware found the device, but it is not supported by load.

0 > boot yy:0/netbsd 
RESETing to change Configuration!
yy:0 doesn't exist, so Open Firmware ignores the string and uses the default parameters to boot MacOS; the MacOS boot routine then clears some of the Open Firmware variables.

0 > boot ata/ata-disk@0:9 specified partition is not bootable 
 ok
As it says.

0 > boot ata/ata-disk@0:0 
>> NetBSD/macppc OpenFirmware Boot, Revision 1.3 
>> (root@nazuha, Fri Jun  8 22:21:55 JST 2001) 
no active package3337696/
and hangs: See the real-base part in the FAQ.

SEE ALSO

installboot(8)

INSTALL.html

 
http://www.NetBSD.org/ports/macppc/faq.html
 
http://www.NetBSD.org/docs/network/netboot/

STANDARDS

IEEE Std 1275-1994 (“Open Firmware”)

BUGS

ofwboot can only boot from devices recognized by Open Firmware.

Early PowerMacintosh systems (particularly the 7500) seem to have problems with netbooting. Adding an arp entry at the tftp server with

arp -s booting-host-name its-ethernet-address
may resolve this problem (see arp(8)).

0 > boot CLAIM failed 
 ok
Once boot failed, successive boots may not be possible. You need to type reset-all or power-cycle to initialize Open Firmware.
August 18, 2001 NetBSD 6.1