Unified Extensible Firmware Interface
In 2011, Microsoft announced that computers certified to run its Windows 8 operating system had to release with Microsoft's public key enrolled and Secure Boot enabled. Following the announcement, Microsoft was accused by critics and free software/open source advocates (including the Free Software Foundation) of trying to use the Secure Boot functionality of UEFI to prevent the installation of alternative operating systems such as Linux. Microsoft denied that the Secure Boot requirement was intended to serve as a form of lock-in. They also clarified its requirements by stating that 32-bit-based systems certified for Windows 8 must allow Secure Boot to enter custom mode or be disabled, but not on systems using the ARM architecture. Windows 10 allows OEMs to decide whether or not Secure Boot can be changed by users of their 32-bit systems.