EFI Firmware Volume Block Specification v0.9
Intel® Platform Innovation Framework for EFI firmware volume block specification, version 0.9.
This specification defines a format for storing firmware volumes in block access type devices for an implementation of the Intel® Platform Innovation Framework for EFI (hereafter referred to as the “Framework”). It is designed to scale to many types of block devices. This specification does the following:
• Defines a firmware volume
• Describes how to implement the firmware volume block protocol and firmware volume Hand-Off Blocks (HOBs)
• Defines a firmware volume header structure and a block-oriented protocol interface that are architecturally required by the Intel® Platform Innovation Framework for EFI architecture specification
This document is intended for the following readers:
• Independent hardware vendors (IHVs) and original equipment manufacturers (OEMs) who will be implementing firmware components that are stored in firmware volumes
• BIOS developers, either those who create general- purpose BIOS and other firmware products or those who modify these products for use in Intel® architecture–based products
Data structure descriptions
Intel® processors based on 32-bit Intel® architecture (IA-32) are “little endian” machines. This distinction means that the low-order byte of a multibyte data item in memory is at the lowest address, while the high-order byte is at the highest address. Processors of the Intel® Itanium® processor family may be configured for both “little endian” and “big endian” operation. All implementations designed to conform to this specification will use “little endian” operation.
In some memory layout descriptions, certain fields are marked reserved. Software must initialize such fields to zero and ignore them when read. On an update operation, software must preserve any reserved field. September, 2003.
Read the full EFI Firmware Volume Block Specification.