The primary methods for modifying boot behavior on an x86 based system are as follows:
By using the eeprom command.
The eeprom command is used to assign a different value to a standard set of properties. These values, which are equivalent to the SPARC OpenBoot PROM NVRAM variables, are stored in the /boot/solaris/bootenv.rc file. Changes that are made to boot behavior by using the eeprom command persist over each system reboot and are preserved during a software upgrade. You can override these changes by editing the GRUB menu at boot time or by editing the menu.lst file. See the eeprom(1M) man page for more information.
Changes that are made by directly editing the bootenv.rc file are not always preserved during a software upgrade. This method is therefore discouraged. The preferred method for making these types of changes is to use the eeprom command.
By editing the GRUB menu at boot time.
Changes that are made by modifying the GRUB kernel behavior at boot time override options that you set by using the eeprom command. However, these changes only remain in effect until the next time you boot the system. See the kernel(1M) man page for more information.
By manually editing the GRUB menu.lst file.
Any system-generated changes that are made to menu.lst entries are changed or lost during a system upgrade. However, any new boot entries that were manually added remain after an upgrade. You can override eeprom settings by editing the GRUB menu at boot time or by editing the menu.lst file. Changes made by editing the GRUB menu at boot time do not persist. Whereas, changes that are made by editing the menu.lst file persist over system reboots.
Become superuser or assume an equivalent role.
Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services.
Change the specified parameter.
# eeprom parameter=new-value
Verify that the new parameter has been set.
# eeprom parameter
The output should display the new eeprom value for the specified parameter.
This example shows how to manually specify that the system boot a 64-bit kernel. The system must support 64-bit computing.
# eeprom boot-file=kernel/amd64/unix
This example shows how to manually boot a 32-bit kernel on a 64-bit capable system.
# eeprom boot-file=kernel/unix
This example shows how to restore the default auto detected boot behavior on a system.
# eeprom boot-file=""