Intel Extensible Firmware Interface - page 340

Extensible Firmware Interface Specification
322 12/12/00 Version 1.02
FilePathList A packed array of EFI device paths. The first element of the array is an
EFI device path that describes the device and location of the Image for
this load option. The FilePathList[0] is specific to the device
type. Other device paths may optionally exist in the FilePathList,
but their usage is OSV specific. Each element in the array is variable
length, and ends at the device path end structure. Because the size of
Description is arbitrary, this data structure is not guaranteed to be
aligned on a natural boundary. This data structure may have to be copied
to an aligned natural boundary before it is used.
OptionalData The remaining bytes in the load option variable are a binary data buffer
that is passed to the loaded image. If the field is zero bytes long, a Null
pointer is passed to the loaded image.
Related Definitions
//*******************************************************
// Attributes
//*******************************************************
#define LOAD_OPTION_ACTIVE 0x00000001
Description
Calling SetVariable() creates a load option. The size of the load option is the same as the size
of the DataSize argument to the SetVariable() call that created the variable. When
creating a new load option, all undefined attribute bits must be written as zero. When updating a
load option, all undefined attribute bits must be preserved. If a load option is not marked as
LOAD_OPTION_ACTIVE, the boot manager will not automatically load the option. This
provides an easy way to disable or enable load options without needing to delete and re-add them.