Two UEFI startup Modes

Source: Internet
Author: User

Two UEFI startup Modes

The UEFI start mode is completely different from the traditional Lagency start mode, so it is necessary to first understand the uefi bios and UEFI start Mode

1. Several UEFI problems that must be clarified
(1) UEFI start mode and legacy start Mode
Legacy Startup Mode: This is the startup mode that PCs have been using for so many years (loading startup programs from MBR ), uefi bios, as a new BIOS, should naturally be compatible with this old startup method;

UEFI Startup Mode: new startup technology under uefi bios. If your PC is preinstalled with Win8 in UEFI startup mode, you will find two small hidden partitions. One is ESP (EFI system partition), and the other is MSR (Microsoft reserved partition, usually 128 MB ). MSR is required for windows. ESP is very important for the UEFI startup mode. The UEFI boot program stores files suffixed with. efi in the ESP partition, And the ESP partition uses the fat32 file system. In addition, there may be a small partition named WinRE Tools, which is the restored partition of win8 and has a small size. Therefore, do not delete these three partitions. But what makes sense for us is the ESP partition. in windows, to access the ESP partition, you must use the partition tool to assign a drive letter to it and unhide it. In Ubuntu, you can directly mount the partition to/boot/efi, you can directly use the folder browser to view the various types. efi file.

Therefore, the first key issue is to determine your startup mode by entering the BIOS. Then you will find that there is a "boot mode", and selecting "UEFI boot" is the UEFI startup mode, select "Legacy boot" as the Legacy startup mode. Uefi bios, which has been seen by Alibaba Cloud: it has a very gorgeous BIOS interface and supports mouse, but only Legacy boot is supported.

(2) UEFI Boot Mode only supports 64-bit systems, so the pre-installed win8 is 64-bit, ubuntu (kylin) also needs 64-bit.

(3) uefi bios and Legacy BIOS
We all know that you can adjust the startup priority of a device in the traditional bios. In UEFI Boot Mode, uefi bios can not only adjust the priority of the device, but also adjust the priority of the boot program on the device, after ubuntu is installed, you can enter the BIOS to find an alternative startup Item named ubuntu. In addition, uefi bios has introduced some new technologies, such as Fast boot and secure boot. Of course, the latter one is completely used for protection.

(4) How to boot from a USB flash drive or a mobile hard drive in UEFI Startup Mode
As long as there is a fat32 partition on the USB flash drive or mobile hard disk, and the root directory of the partition has a folder named EFI, UEFI will automatically find the corresponding Startup file (. efi)
If you have just created a ubuntu (kylin)-13.04-64-bit boot USB flash drive, you can open it and you will find that the partition file system is fat32 and there is indeed an EFI folder, let's look at the various types. efi boot file (64-bit again here, you cannot find this folder in 32-Bit mode ). Therefore, it is easy to create a portable USB flash drive or a mobile hard drive. You just need to copy and paste it.
Some uefi bios also supports searching startup files from the NTFS partition.


For example, Lenovo's computer and EFI settings:

If you select EFI in the startup mode, only EFI is supported. If you select legacy, both of them are supported,
Then, you can choose whether to prioritize EFI or leagacy in another option.

Then, you can sort the device startup order in two modes in boot.

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