We often hear the terms BIOS and UEFI. But do you know how BIOS and UEFI work?
Most computer users only know that if we turn on the computer, it will be preceded by a display of hardware information which is a report of the results of the BIOS/UEFI before the computer loads the operating system.
Difference between BIOS and UEFI
BIOS stands for Basic Input/Output System and is also known as system BIOS, ROM BIOS or PC BIOS. While the definition of BIOS is the firmware used to initialize the hardware during the boot process (power-on startup ), and to provide runtime services for the operating system and programs.
The BIOS firmware is pre-installed on the computer’s motherboard and is the first software that runs when the computer is turned on.
The BIOS is stored in an EPROM (Erasable Programmable Read-Only Memory) which allows the manufacturer to perform updates easily.
You can access the BIOS by pressing del, F2 or F10 during the initial phase of the boot procedure
Unified Extensible Firmware Interface or what we usually call UEFI is the software between operating system and firmware. UEFI replaces the legacy Basic Input/Output System (BIOS) firmware interface that was originally on all computers with most UEFI firmware implementations providing support for legacy BIOS services.
UEFI can support remote diagnostics and repair of computers, even without an operating system installed.
BIOS and UEFI have the same task, namely initializing hardware components and starting the operating system stored on the hard disk drive when the computer starts up.
The main difference between UEFI and BIOS is that UEFI stores all data about initialization and startup in a .efi, whereas the BIOS stores it in the firmware.
files. This efi is stored in a special partition called the EFI System Partition (ESP) on the hard disk. This ESP partition also contains the bootloader.
Advantages of using UEFI
UEFI came as a refinement of the shortcomings of the BIOS. As a BIOS enhancement, of course, UEFI has many advantages over its predecessors. Some of the advantages of UEFI, among others:
- UEFI supports drive and partition sizes up to 8 ZB (zettabyte), while BIOS only supports 2 TB (terabyte).
- UEFI supports an unlimited number of partitions, whereas BIOS can only create 4 primary partitions.
- Boot time using EUFI is faster.
- UEFI offers “Secure Boot” security to prevent the computer from booting from unauthorized applications and to ensure that no malware interferes with the startup process .
- UEFI supports network functions in the UEFI firmware itself, which helps remote troubleshooting and UEFI configuration.
- UEFI runs in 32bit or 64bit mode which is capable of providing GUI navigation with a mouse, while BIOS runs in 16bit mode and navigates using only the keyboard.
How to check Windows using UEFI or Legacy BIOS mode
1. Open “System Information”.
Click search and type “System Information”. Then select the application ” System Information “
2. Check the item “BIOS Mode”
If the item “BIOS Mode” is “ UEFI ”, it means that you have used UEFI boot mode. On the other hand, if the value is “ Legacy ”, it means that you are still using the Legacy BIOS boot mode.
How to change boot mode from Legacy BIOS to UEFI on Windows without reinstalling and losing data
1. Check Windows version > 1703
2. Check whether the partition type is using MBR
Open ” Disk Management “, for how to open it you can see on How to create a Windows partition without losing data and without applications.
In “Disk Management”, select Disk 0 (Windows installation disk) and then right-click and select “Properties”. In the “Properties” window select the “Volumes” tab and look at the “Partition style” what is the MBR.
3. Open Command prompt “CMD” and run as administrator
4. Change MBR to GPT with mbr2gpt.exe
In the CMD window type the following command:
mbr2gpt.exe /convert /allowfullOS
wait until all the process is complete
5. Restart the computer and enter BIOS Setup
Restart the computer after step 4 is completely finished. Then enter BIOS setup by pressing the keyboard key del, F2, or F10 (see your computer’s user manual for details ) during the initial phase of the boot procedure before loading Windows.
6 . Change boot mode in BIOS Setup to “UEFI”
7. Save and exit BIOS Setup.
8. Boot Windows 10 normally.
That’s an easy way to change the boot mode from Legacy BIOS to UEFI on Windows without reinstalling and losing data and without using third-party applications.
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