The Unified EFI Specification Defines an Interface Between an Operating System and Platform Firmware

The Intel® Platform Innovation Framework for Unified Extensible Firmware Interface (UEFI) architecture specification describes the primary design elements of an innovative approach to constructing platform firmware for platforms based on Intel® architecture.

The design is characterized by a central framework that provides services and infrastructure to combine modular software building block elements.

Together, the infrastructure code (which is known as the foundation) and an appropriate selection of modular building blocks constitute a complete platform software implementation that is designed to initialize the platform and boot shrink-wrap operating systems or other custom application environments.

The foundations comprise the pre-EFI initialization (PEI) and driver execution environment (DXE) phases, which are both described in this specification.

In addition, this specification describes a number of other design elements in an effort to provide a complete set of baseline design and services support for arbitrary building blocks that will customize a particular platform firmware image to the hardware, and the intended purpose and market for that hardware.

Additional design elements include security services, boot-device policy management, runtime services, afterlife, firmware storage, user interface, firmware integrity services, manageability support, legacy compatibility, and boot or resume paths.

Interoperability and Component Specifications

The interoperability and component specifications describe in greater depth the functional components that complement the PEI and DXE foundations, and that are also architectural in the framework design.

“Architectural,” in this context, implies that the functional components provide services that may always be assumed to be present by any code designed and written to operate across a range of platforms that use firmware based on the framework design.

Specification Downloads

The following specifications for the Intel® Platform Innovation Framework for UEFI are available for download.

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Extensible Firmware Interface Specification Overview

This page contains EFI specification information for EFI 1.10 and EFI 1.02 Specifications only, and these specifications are still available for download from this site. However, the latest specification for EFI has been merged with the UEFI specification and members can download these specifications from the Unified Extensible Firmware Interface (UEFI) website.

EFI Specification

You may download the EFI Specification version 1.10, download a document outlining the changes between the draft 0.95 and the final version, or access related specifications:

  • Download the Specification 1.10 Update -001. EFI Specification 1.10 update -001 contains clarifications and corrections that were submitted and accepted between 1/7/2003 and 11/1/2003, after the formal EFI Specification 1.10 was released.