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OpenBoot NVRAM


List, change, and restore default NVRAM parameters.

  • View and change NVRAM parameters from the shell.

System configuration variables are stored in system NVRAM. These OpenBoot variables determine the startup machine configuration and related communication characteristics. If you modify the values of the configuration variables, any changes you make remain in effect even after a power cycle. Configuration variables should be adjusted cautiously, however, because incorrect settings can prevent a system from booting.

Table 3.7 describes OpenBoot's NVRAM configuration variables, their default values, and their functions.

Table 3.7. NVRAM Variables






The system starts up automatically after power-on or reset if auto-boot? is true. If it is set to false, the system stops at the OpenBoot prompt (ok) after power-on or reset.



The command that is executed if auto-boot? is true.


disk or net

The device from which to start up.


Empty string

Arguments passed to the started program.



The diagnostic startup source device.


Empty string

Arguments passed to the startup program in diagnostic mode.



Whether to run in diagnostic mode.



Whether name fields are included for plug-in device FCodes.



A console input device (usually keyboard, ttya, or ttyb).



The contents of NVRAMRC.


Empty string

A custom original equipment manufacturer (OEM) banner (enabled with oem-banner? true).



If true, use custom OEM banner.


No default

A byte array custom OEM logo (enabled with oem-logo? true). Displayed in hexadecimal.



If true, use custom OEM logo; otherwise, use the Sun logo.



A console output device (usually screen, ttya, or ttyb).



Which SBus slots to probe and in what order.



The number of onscreen columns (characters/line).



The number of onscreen rows (lines).


No default

The number of incorrect security password attempts.



The firmware security level (options: none, command, or full).


No default

The firmware security password (which is never displayed).



If true, execute commands in NVRAMRC during system startup.


OpenBoot Versions Because older SPARC systems use older versions of OpenBoot, they might use different defaults or different configuration variables from those shown in Table 3.7. This text describes OpenBoot version 4.

You can view and change the NVRAM configuration variables by using the commands listed in Table 3.8.

Table 3.8. Commands for Viewing and Modifying Configuration Variables




Sets the security password.


Displays the current value and the default value for each variable. To show the current value of a named variable, you type the following:


printenv <parameter-name>

setenv <variable> <value>

Sets <variable> to the given decimal or text <value>. Changes are permanent, but they often take effect only after a reset.

set-default <variable>

Resets the value of a specified <variable> to the factory default.


Resets ALL OpenBoot variable values to the factory defaults.

The following examples illustrate the use of the commands described in Table 3.8. All commands are entered at the ok OpenBoot prompt.

You use the printenv command, with no argument, to display the current value and the default value for each variable:

ok printenv

The system responds with this:

Variable Name         Value                          Default Value
tpe-link-test?        true                           true
scsi-initiator-id     7                              7
keyboard-click?       false                          false
ttyb-rts-dtr-off      false                          false
ttyb-ignore-cd        true                           true
ttya-rts-dtr-off      false                          false
ttya-ignore-cd        true                           true
ttyb-mode             9600,8,n,1,-                   9600,8,n,1,-
ttya-mode             9600,8,n,1,-                   9600,8,n,1,-
pcia-probe-list       1,2,3,4                        1,2,3,4
pcib-probe-list       1,2,3                          1,2,3
mfg-mode              off                            off
diag-level            max                            max
#power-cycles         89
fcode-debug?          false                          false
output-device         screen                         screen
input-device          keyboard                       keyboard
load-base             16384                          16384
boot-command          boot                           boot
auto-boot?            false                          true
watchdog-reboot?      false                          false
diag-device           net                            net
boot-device           disk:a disk net                disk net
local-mac-address?    false                          false
ansi-terminal?        true                           true
screen-#columns       80                             80
screen-#rows          34                             34
silent-mode?          false                          false
use-nvramrc?          false                          false
security-mode         none
security-#badlogins   0
oem-logo?             false                          false
oem-banner?           false                          false
diag-switch?          false                          false


The printenv Command Depending on the version of OpenBoot that you have on your system, the printenv command might show slightly different results. This example uses a system running OpenBoot version 3.31.

To set the auto-boot? variable to false, you type the following:

ok setenv auto-boot? false

The system responds with this:

auto-boot? =   false

You can verify the setting by typing the following:

ok printenv auto-boot?

The system responds with this:

auto-boot? =     false

To reset the variable to its default setting, you type the following:

ok set-default auto-boot?

The system does not respond with a messageonly another OpenBoot prompt. You can verify the setting by typing the following:

ok printenv auto-boot?

The system responds with this:

auto-boot? =     true

To reset all variables to their default settings, you type the following:

ok set-defaults

The system responds with this:

Setting NVRAM parameters to default values.

It's possible to set variables from the Unix command line by issuing the eeprom command. You must be logged in as root to issue this command, and although anyone can view a parameter, only root can change the value of a parameter. For example, to set the auto-boot? variable to true, you type the following at the Unix prompt (note the use of quotes to escape the ? from expansion by the shell):

eeprom 'auto-boot?=true'

Any non-root user can view the OpenBoot configuration variables from a Unix prompt by typing the following:


For example, to change the OpenBoot parameter security-password from the command line, you must be logged in as root and issue the following command:

example# eeprom security-password=
Changing PROM password:
New password:
Retype new password:


Setting the OpenBoot Security Mode Setting the security mode and password can be dangerous: If you forget the password, the system is unable to boot. It is nearly impossible to break in without sending the CPU to Sun to have the PROM reset. OpenBoot security is discussed more in the section "OpenBoot Security," later in this chapter.

The security mode password you assign must be between zero and eight characters. Any characters after the eighth are ignored. You do not have to reset the system after you set a password; the security feature takes effect as soon as you type the command.

With no parameters, the eeprom command displays all the OpenBoot configuration settings, similar to the OpenBoot printenv command.

Use the prtconf command with the -vp options to view OpenBoot parameters from the shell prompt as follows:

prtconf -vp

The system responds with a great deal of output, but you'll see the following OpenBoot information embedded in the output:

. . . . <output truncated>
ansi-terminal?:  'true'
        screen-#columns:  '80'
        screen-#rows:  '34'
        silent-mode?:  'false'
        use-nvramrc?:  'false'
        security-mode: 'none'
        security-#badlogins:   '0'
        oem-logo?:  'false'
        oem-banner?:  'false'
        diag-switch?:  'false'
        name:  'options'

   Node 0xf002ce38
        screen:  '/pci@1f,0/pci@1,1/SUNW,m64B@2'
        net:  '/pci@1f,0/pci@1,1/network@1,1'
        cdrom:  '/pci@1f,0/pci@1,1/ide@3/cdrom@2,0:f'
        disk:  '/pci@1f,0/pci@1,1/ide@3/disk@0,0'
        disk3:  '/pci@1f,0/pci@1,1/ide@3/disk@3,0'
        disk2:  '/pci@1f,0/pci@1,1/ide@3/disk@2,0'
        disk1:  '/pci@1f,0/pci@1,1/ide@3/disk@1,0'
        disk0:  '/pci@1f,0/pci@1,1/ide@3/disk@0,0'
        ide:  '/pci@1f,0/pci@1,1/ide@3'
. . . <output truncated>


Resetting NVRAM Variables On non-USB style keyboards, not USB keyboards, if you change an NVRAM setting on a SPARC system and the system no longer starts up, you can reset the NVRAM variables to their default settings by holding down Stop+N while the machine is powering up. When you issue the Stop+N key sequence, you hold down Stop+N immediately after turning on the power to the SPARC system; you then keep these keys pressed for a few seconds or until you see the banner (if the display is available).

These are both good techniques for forcing a system's NVRAM variables to a known condition.

You can use the NVRAM commands listed in Table 3.9 to modify device aliases so that they remain permanent, even after a restart.

Table 3.9. NVRAM Commands



nvalias <alias> <device-path>

Stores the command devalias <alias><device-path> in NVRAMRC. (The alias persists until the nvunalias or set-defaults command is executed.) This command turns on use-nvramrc?.

nvunalias <alias>

Deletes the corresponding alias from NVRAMRC.

For example, to permanently create a device alias named bootdisk that represents a SCSI disk with a target ID of 3 on an Ultra 5 system, you type the following:

nvalias bootdisk /pci@1f,0/pci@1,1/ide@3/disk@3,0

Because disk device pathnames can be long and complex, the show-disks command is provided to assist you in creating device aliases. Type the show-disks command and a list of disk devices is shown as follows:

ok show-disks
a) /pci@1f,0/pci@1,1/ide@3/cdrom
b) /pci@1f,0/pci@1,1/ide@3/disk
c) /pci@1f,0/pci@1,1/ebus@1/fdthree@14,3023f0
Enter Selection, q to quit:

Type b to select an IDE disk and the system responds with the following message:

/pci@1f,0/pci@1,1/ide@3/disk has been selected.
Type ^Y ( Control-Y ) to insert it in the command line.
e.g. ok nvalias mydev ^Y for creating devalias mydev for

Now create a device alias named mydisk followed by ctrl+y as follows:

nvalias mydisk ^Y

The system pastes the selected device path as follows:

ok nvalias mydisk /pci@1f,0/pci@1,1/ide@3/disk

Now all you need to do is add the target number and logical unit number (for example, sd@0,0 or disk@0,0) to the end of the device name as follows:

ok nvalias mydisk /pci@1f,0/pci@1,1/ide@3/disk@0,0


Specifying the Disk Slice If the boot slice of the disk device that you wish to boot to is not slice 0, you will need to add the disk slice letter to the end of the device name as follows:

ok nvalias mydisk /pci@1f,0/pci@1,1/ide@3/disk@0,0:b

In the example, I used the letter "b," which corresponds to disk slice 1. This is one area where you'll find disk slices identified by an alpha character and not a number. The letter "a" corresponds to slice 0, "b" is slice 1, etc. If no letter is specified, "a" for slice 0 is assumed. For example, /pci@1f,0/pci@1,1/ide@3/disk@0,0 is the same as specifying /pci@1f,0/pci@1,1/ide@3/disk@0,0:a.

To remove an alias, type nvunalias <aliasname>. For example, to remove the devalias named mydisk, type

ok nvunalias mydisk

The alias named mydisk will no longer be listed after the next OpenBoot reset.

The nvedit Line Editor

Optionally, you can use nvedit to create your device aliases. On systems with a PROM version of 1.x or 2.x, the nvalias command might not be available and you must use nvedit to create custom device aliases. nvedit is an OpenBoot line editor that edits the NVRAMRC directly, has a set of editing commands, and operates in a temporary buffer. The following is a sample nvedit session:

ok setenv use-nvramrc? true


Learning nvedit This section is included for information purposes, to show an additional method for modifying the NVRAM. The nvedit line editor will not be covered on the certification exam.

The system responds with the following:

use-nvramrc? =     true
ok nvedit

  0: devalias bootdisk /pci@1f,0/pci@1,1/ide@3/disk@0,0
1: <Control-C>
ok nvstore
ok reset-all
   Resetting ......
ok boot bootdisk

The preceding example uses nvedit to create a permanent device alias named bootdisk. The example uses Ctrl+C to exit the editor. It also uses the nvstore command to make the change permanent in the NVRAMRC. Then, it issues the reset-all command to reset the system and then boots the system from bootdisk by using the boot bootdisk command.

Table 3.10 lists some of the basic commands you can use while in the nvedit line editor.

Table 3.10. nvedit Commands




Moves backward to beginning of the line.


Moves backward one character.


Moves backward one word.


Exits the script editor, returning to the OpenBoot command interpreter. The temporary buffer is preserved but is not written back to the script. You use nvstore afterward to write it back.


Erases the next character.


Erases from the cursor to the end of the word, storing the erased characters in a save buffer.


Moves forward to the end of the line.


Moves forward one character.


Moves forward one word.


Erases the previous character.


Erases from the beginning of the word to just before the cursor, storing erased characters in a save buffer.


Erases from the cursor position to the end of the line, storing the erased characters in a save buffer. If at the end of a line, it joins the next line to the current line (that is, deletes the new line).


Displays the entire contents of the editing buffer.


Moves to the next line of the script-editing buffer.


Inserts a new line at the cursor position and stays on the current line.


Moves to the previous line of the script-editing buffer.


Quotes the next character (that is, allows you to insert control characters).


Retypes the line.


Erases the entire line, storing the erased characters in a save buffer.


Erases from the beginning of the word to just before the cursor, storing erased characters in a save buffer.


Inserts the contents of the save buffer before the cursor.

Return (Enter)

Inserts a new line at the cursor position and advances to the next line.


Erases the previous character.


Erases the previous character.

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