The boot device is specified by the setting of an OpenBoot configuration variable called boot-device. The default setting of this variable is disk net. Because of this setting, the firmware first attempts to boot from the system hard drive, and if that fails, from the on-board NET0 Gigabit Ethernet interface.
This procedure assumes that you are familiar with the OpenBoot firmware and that you know how to enter the OpenBoot environment. For more information, see the Sun SPARC Enterprise T5140 and T5240 Servers Administration Guide.
Note - The serial management port on the ILOM card is preconfigured as the default system console port. For more information, see the Sun SPARC Enterprise T5140 and T5240 Servers Overview.
If you want to boot from a network, you must connect the network interface to the network.
Sun SPARC Enterprise T5140 and T5240 Servers Overview