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<!doctype linuxdoc system>
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<manpage title="NVSETENV" sectnum="8">
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<bf/nvsetenv/ - change/view OF's environment boot-variables
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<tt/[/<em/variable/ <tt/[/<em/value/<tt/<bf/]]//
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<sect1> DESCRIPTION<p>
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<bf/nvsetenv/ is a program to adjust or view the Open Firmware (OF)
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boot parameters stored in non-volatile (battery-powered) RAM on your
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<bf/nvsetenv/ will show the current values of all OF's environment
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variables when no parameters are given.
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<tag/<em>variable</em>/ nvsetenv will show current value of an OF's
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variable, if no value is given
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<tag/<em>variable value</em>/ nvsetenv will set <em>variable</em> to
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This example will set the boot device to the first SCSI disk on the
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internal SCSI bus, using /vmlinux as boot image, trying to
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use the third partition as root partition.
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> nvsetenv boot-device "scsi-int/sd@0:0"
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> nvsetenv boot-file " /vmlinux root=/dev/sda3"
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Alternatives boot devices are:
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scsi/sd@1:0 SCSI disk at ID 1
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ata/ata-disk@0:0 Internal IDE disk
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You can also boot from a floppy, you need a XCOFF-format kernel image
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(in this example: vmlinux.coff), copied to a HFS format high-density
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> nvsetenv boot-device "fd:vmlinux.coff"
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> nvsetenv boot-file " root=/dev/sda3"
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To return to MacOS, do:
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> nvsetenv boot-device "/AAPL,ROM"
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Valid values for "input-devices" are:
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ttya Modem serial port
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ttyb Printer serial port
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enet Ethernet interface
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Valid values for "output-devices" are (machine and/or OF dependent):
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screen Screen display (newer machines)
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/chaos/control Screen display (7500, 7600 and 8500)
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/bandit/ATY,264GT-B Screen display (6500)
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OF is not designed to wait for your hard disk to spin up
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(remember MacOS boots from ROM).
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Use the following setting to have OF retry to boot from your disk
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> nvsetenv boot-command "begin ['] boot catch 1000 ms cr again"
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You only have to append an "S" to the "boot-file" variable to boot
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Linux in single user mode.
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needs the following device:
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<tag><em>/dev/nvram</em></tag> character device with major number 10
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<verb>Paul Mackerras <paulus@cs.anu.edu.au> (program)</verb>
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<verb>Richard van Hees <R.M.vanHees@phys.uu.nl> (documentation)</verb>
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