Why UEFI Is Replacing BIOS: Speed, Security, and Flexibility Explained

When EFI reached version 1.1, Intel released it publicly; version 2.0 attracted many companies, and the specification became managed by the Unified EFI Forum, renaming EFI to UEFI (Unified Extensible Firmware Interface).

UEFI can be seen as an upgraded BIOS with stronger functionality and more convenient usage, though the boot media must be specially prepared.

UEFI is a newer motherboard boot option considered the successor to the over‑20‑year‑old BIOS, offering faster startup by skipping the traditional self‑test (POST) process. The legacy BIOS mode is still available alongside UEFI.

Unlike traditional BIOS, UEFI supports graphical interfaces and mouse operation, allowing a more user‑friendly setup experience.

Advantages of UEFI over BIOS:

1. Security – UEFI requires a dedicated EFI system partition, isolating boot files from the OS and enabling Secure Boot, which uses stored certificates to verify signed boot loaders before loading the operating system, preventing malicious code execution.

2. Flexible boot – Similar to GRUB, UEFI can invoke an EFIShell to load specific hardware drivers and select boot files. If the default boot fails, the EFIShell can load a boot file from a USB drive to continue the startup.

3. Larger storage support – Traditional BIOS with MBR cannot boot drives larger than 2.1 TB, whereas UEFI (using GPT) supports much larger capacities, making it the mainstream choice as high‑capacity drives become common.

Modern motherboards usually provide three boot mode options:

Auto (Both) : automatically follows the device order, preferring UEFI when possible.

UEFI only : boots only devices that support UEFI.

Legacy only : boots only devices that support the traditional BIOS (Legacy) mode.

If you need to use Legacy mode, enable the Compatibility Support Module (CSM) in the BIOS, which allows older hardware and operating systems that lack UEFI support to boot.

In BIOS settings, "Enable" means the option is turned on and "Disabled" means it is turned off. It is recommended to set a fixed boot mode (UEFI or Legacy) rather than leaving it on automatic, to avoid boot failures or blue‑screen loops caused by mismatched boot media.