Intel Extensible Firmware Interface - Manual (Page 363)

Protocols — Bootable Image Support
Version 1.10 12/01/02 11-3
If BootPolicy is TRUE the firmware’s boot manager is attempting to load an EFI image that is a
boot selection. In this case, FilePath contains the file path value in the boot selection option.
Normally the firmware would implement the policy on how to handle an inexact boot file path;
however, since in this case the firmware cannot interpret the file path, the
LoadFile() function
is responsible for implementing the policy. For example, in the case of a network boot through the
PXE Base Code protocol,
FilePath merely points to the root of the device, and the firmware
interprets this as wanting to boot from the first valid loader. The following is list of events that
LoadFile() will implement for a PXE boot:
• Perform DHCP.
• Optionally prompt the user with a menu of boot selections.
• Discover the boot server and the boot file.
• Download the boot file into
Buffer and update BufferSize with the size of the boot file.
Status Codes Returned
EFI_SUCCESS The file was loaded.
EFI_UNSUPPORTED The device does not support the provided BootPolicy .
EFI_INVALID_PARAMETER FilePath is not a valid device path, or BufferSize
is NULL .
EFI_NO_SUCH_MEDIA No medium was present to load the file.
EFI_DEVICE_ERROR The file was not loaded due to a device error.
EFI_NO_RESPONSE The remote system did not respond.
EFI_NOT_FOUND The file was not found.
EFI_ABORTED The file load process was manually cancelled.