Intel Extensible Firmware Interface, Specification

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Extensible Firmware Interface Specification
450 12/12/00 Version 1.02
G.4.15.1 Issuing the Command
To issue a NvData command, create a CDB and fill it in as shows in the table below:
CDB Field How to initialize the CDB structure for a NvData command
OpCode PXE_OPCODE_NVDATA
OpFlags Set as needed.
CPBsize
sizeof(PXE_CPB_NVDATA)
DBsize sizeof(PXE_DB_NVDATA)
CPBaddr
Address of
PXE_CPB_NVDATA
structure.
Dbaddr
Address of
PXE_DB_NVDATA
structure.
StatCode PXE_STATCODE_INITIALIZE
StatFlags PXE_STATFLAGS_INITIALIZE
Ifnum
A valid interface number from zero to
!PXE.IFcnt
.
Control Set as needed.
Preparing the CPB
There are two types of non-volatile data CPBs, one for sparse updates and one for bulk updates.
Sparse updates allow updating of single non-volatile storage items. Bulk updates always update all
non-volatile storage items. Check the
!PXE.Implementation
flags to see which type of non-
volatile update is supported by this UNDI and network device.
If you do not need to update the non-volatile storage set the
CDB.CPBsize
and
CDB.CPBaddr
fields to
PXE_CPBSIZE_NOT_USED
and
PXE_CPBADDR_NOT_USED
.