Successor to the antiquated BIOS, the Unified Extensible Firmware Interface (UEFI) adds powerful security tools to post-XP systems.
Ironically, UEFI can also block important repair, recovery, and backup tools that boot from DVDs, CDs, or USB drives.
Windows 8’s tight integration with a PC’s UEFI can be especially problematic when you need to run bootable rescue media. This article will show how to fully master the UEFI boot system on Vista, Windows 7, and Windows 8 systems. At the end, you’ll have the benefits of UEFI security but also know how to bypass its drawbacks.
The many strengths — and weaknesses — of UEFI
From the start, all PCs have contained low-level, semipermanent software that wakes up a system’s components in the correct order and then hands off overall control to whatever operating system is installed.
In old systems, that software was the Basic Input/Output System, known to nearly all PC users as the BIOS. Commonly called “firmware,” the BIOS was specifically designed to be rarely, if ever, changed or updated. Its sole function was to initiate system startup.
As PCs became more powerful, the BIOS became effectively obsolete (more info). A more powerful and flexible replacement for the BIOS — UEFI — first appeared in PCs in 2005. It’s essentially ubiquitous in newer machines. In fact, it’s likely that the PC you’re using right now is UEFI-based.
Most early versions of UEFI, such as those found in Vista PCs, simply mimicked the limited capabilities of the classic BIOS. Then, a slightly more useful UEFI showed up in many machines sold with Win7. Users could, for example, access the UEFI settings while Windows was running; the UEFI could also access multi-terabyte hard drives and allow vendor-specific enhancements.
How to solve UEFI boot and startup problems