Modifying Boot Parameters on a SPARC Based System

The boot PROM is used to boot a SPARC based system and to modify boot parameters. For example, you might want to reset the device from which to boot, change the default boot file or kernel, or run hardware diagnostics before bringing the system to a multiuser state.

If you need to perform any of the following tasks, you need to change the default boot device:

Add a new drive to the system either permanently or temporarily
Change the network boot strategy
Temporarily boot a stand-alone system from the network

For a complete list of PROM commands, see the monitor(1M) and eeprom(1M) man pages.

How to Identify the PROM Revision Number for a System

Bring the system to the ok PROM prompt.For more information, see How to Shut Down a System by Using the init Command.
Display a system’s PROM revision number by using the banner command.
```
ok banner
```

How to Identify Devices on a System

You might need to identify the devices on a system to determine the appropriate devices from which to boot.

Before You Begin

Before you can safely use the probe commands to determine what devices are attached to the system, you need to do the following:

Change the PROM auto-boot? parameter to false.
```
ok setenv auto-boot? false
```
Issue the reset-all command to clear system registers.
```
ok reset-all
```

You can view the probe commands that are available on your system by using the sifting probe command:

ok sifting probe

If you run the probe commands without clearing the system registers, the following message is displayed:

ok probe-scsi
This command may hang the system if a Stop-A or halt command
has been executed.  Please type reset-all to reset the system 
before executing this command. 
Do you wish to continue? (y/n) n

Identify the devices on the system.
```
ok probe-device
```
(Optional) If you want the system to reboot after a power failure or after you use the reset command, then reset the auto-boot? parameter to true.
```
ok setenv auto-boot? true
auto-boot? =          true
```
Boot the system to a multiuser state.
```
ok reset-all
```

Example 6-1 Identifying the Devices on a System

The following example shows how to identify the devices connected to a system.

ok setenv auto-boot? false
auto-boot? =          false
ok reset-all
SC Alert: Host System has Reset



Sun Fire T200, No Keyboard
.
.
.
OpenBoot 4.30.4.a, 16256 MB memory available, Serial #69069018.
Ethernet address 0:14:4f:1d:e8:da, Host ID: 841de8da.
ok probe-ide
   Device 0  ( Primary Master )
         Removable ATAPI Model: MATSHITACD-RW  CW-8124

  Device 1  ( Primary Slave )
         Not Present

  Device 2  ( Secondary Master )
         Not Present

  Device 3  ( Secondary Slave )
         Not Present

ok setenv auto-boot? true
auto-boot? =          true

Alternatively, you can use the devalias command to identify the device aliases and the associated paths of devices that might be connected to the system. For example:

ok devalias
ttya                     /pci@7c0/pci@0/pci@1/pci@0/isa@2/serial@0,3f8
nvram                    /virtual-devices/nvram@3
net3                     /pci@7c0/pci@0/pci@2/network@0,1
net2                     /pci@7c0/pci@0/pci@2/network@0
net1                     /pci@780/pci@0/pci@1/network@0,1
net0                     /pci@780/pci@0/pci@1/network@0
net                      /pci@780/pci@0/pci@1/network@0
ide                      /pci@7c0/pci@0/pci@1/pci@0/ide@8
cdrom                    /pci@7c0/pci@0/pci@1/pci@0/ide@8/cdrom@0,0:f
disk3                    /pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2/disk@3
disk2                    /pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2/disk@2
disk1                    /pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2/disk@1
disk0                    /pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2/disk@0
disk                     /pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2/disk@0
scsi                     /pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2
virtual-console          /virtual-devices/console@1
name                     aliases

How to Determine the Default Boot Device

Bring the system to the ok PROM prompt.For more information, see How to Shut Down a System by Using the init Command.
Determine the default boot device.
```
ok printenv boot-device
```
boot-device

Identifies the parameter for setting the device from which to boot.

For more information, see the printenv(1B) man page.

The default boot-device is displayed in a format that is similar to the following:
```
boot-device =  /pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2/disk@0,0:a
```
If the boot-device parameter specifies a network boot device, the output is similar to the following:
```
boot-device = /sbus@1f,0/SUNW,fas@e,8800000/sd@a,0:a \
/sbus@1f,0/SUNW,fas@e,8800000/sd@0,0:a disk net
```

How to Change the Default Boot Device by Using the Boot PROM

Before You Begin

You might need to identify the devices on the system before you can change the default boot device to some other device. For information about identifying devices on the system, see How to Identify Devices on a System.

Bring the system to the ok PROM prompt.
```
# init 0
```
Change the value of the boot-device parameter.
```
ok setenv boot-device device[n]
```
device[n]

Identifies the boot-device value, such as disk or network. The n can be specified as a disk number. Use one of the probe commands if you need help identifying the disk number.
Verify that the default boot device has been changed.
```
ok printenv boot-device
```
Save the new boot-device value.
```
ok reset-all
```
The new boot-device value is written to the PROM.

Example 6-2 Changing the Default Boot Device by Using the Boot PROM

In this example, the default boot device is set to disk.

# init 0
# 
INIT: New run level: 0
.
.
.
The system is down.
syncing file systems... done
Program terminated
ok setenv boot-device /pci@1f,4000/scsi@3/disk@1,0
boot-device =         /pci@1f,4000/scsi@3/disk@1,0
ok printenv boot-device
boot-device           /pci@1f,4000/scsi@3/disk@1,0
ok boot
Resetting ... 

screen not found.
Can't open input device.
Keyboard not present.  Using ttya for input and output.
.
.
.
Rebooting with command: boot disk1                                    
Boot device: /pci@1f,4000/scsi@3/disk@1,0  File and args:

In this example, the default boot device is set to the network.

# init 0
# 
INIT: New run level: 0
.
.
.
The system is down.
syncing file systems... done
Program terminated
ok setenv boot-device net
boot-device =         net
ok printenv boot-device
boot-device           net                    disk
ok reset
.
.
.
Boot device: net  File and args:

pluto console login:

How to Change the Default Boot Device by Using the `eeprom` Utility

Become the root role.
Specify the alternate device from which to boot.
```
# eeprom boot-device new-boot-device
```
Verify that the new boot parameter has been set.
```
# eeprom boot-device
```
The output should display the new eeprom value for the boot-device parameter.

How to Change the Default Boot File by Using the Boot PROM

Bring the system to run level 0.
```
# init 0
```
The ok PROM prompt is displayed. For more information, see the init(1M) man page.
Set the boot-file property to an alternate boot file or kernel.
```
ok setenv boot-file boot-file
```
Verify that the default boot file or kernel has been changed.
```
ok printenv boot-file
```
Save the new boot-file value.
```
ok reset-all
```
The new boot-file value is written to the PROM.

How to Change the Default Boot File by Using the `eeprom` Utility

Become the root role.

Specify the alternate boot file or kernel to boot.

# eeprom boot-file new boot-file

For example:

# eeprom boot-file=kernel.name/sparcv9/unix

Verify that the default boot file has been changed.
```
# eeprom boot-file
```