HP 400 Series Servicing Manual page 281

The path to the selected operating system is stored in the EEPROM when you execute
the Auto System Select menu. If your workstation or system environment changes and
the operating system you previously selected as the default has moved to another mass
storage device, you must reconfigure the EEPROM. To reconfigure for the new path to
the operating system you want, enter Configuration Control Mode, select Auto System
Select and reselect the operating system.
The selected and stored operating system automatically boot each time the system unit
is turned on. You may prevent that by entering Attended Mode when you turn the sys-
tem unit on. At this time, you may temporarily select another operating system to
boot.
Configuring the EEPROM C-29