For more information, see Accessing the Preboot Menu.
Preboot> edit
The Preboot menu enters edit mode.
In edit mode, the Preboot menu displays its selections one by one, offering you a chance to change each one.
To change a setting, type the new value, and then press Enter.
To skip to the next setting, press Enter.
To change the serial_is_host setting, type 0, and then press Enter.
The Preboot menu redisplays the serial_is_host setting with the value 0.
The next setting appears.
Enter 'y[es]' to commit changes: [no]
The Preboot menu displays this message:
Summary: Changed 1 settings. Preboot>