Revision Note: V2.0 (February 27, 2014): Revised advisory to rerelease update 2871690. The rereleased update addresses an issue where specific third-party BIOS versions did not properly validate the signature of the original update. Customers who have already successfully installed the original update do not need to take any action. See the Advisory FAQ for more information.Summary: Microsoft is announcing the availability of an update for Windows 8 and Windows Server 2012 that revokes the digital signatures for nine private, third-party UEFI (Unified Extensible Firmware Interface) modules that could be loaded during UEFI Secure Boot. When the update is applied, the affected UEFI modules will no longer be trusted and will no longer load on systems where UEFI Secure Boot is enabled. The affected UEFI modules consist of specific Microsoft-signed modules that are either not in compliance with our certification program or their authors have requested that the packages be revoked. At the time of this release, these UEFI modules are not known to be available publicly.