Intel Extensible Firmware Interface - Manual (Page 74)

Extensible Firmware Interface Specification
3-4 12/01/02 Version 1.10
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 descriptor 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. The
number of bytes in
OptionalData can be computed by
subtracting the starting offset of OptionalData from total
size in bytes of the EFI_LOAD_OPTION .
Related Definitions
//*******************************************************
// Attributes
//*******************************************************
#define
LOAD_OPTION_ACTIVE 0x00000001
#define LOAD_OPTION_FORCE_RECONNECT 0x00000002
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.
If any
Driver#### load option is marked as LOAD_OPTION_FORCE_RECONNECT , then all of
the EFI drivers in the system will be disconnected and reconnected after the last Driver####
load option is processed. This allows an EFI driver loaded with a Driver#### load option to
override an EFI driver that was loaded prior to the execution of the EFI Boot Manager.