Original posts: http://bbs.wuyou.net/forum.php?mod=viewthread&tid=303679
Objective:
1, this tutorial is described for UEFI boot, according to the Universal support UEFI machine to describe
2. This tutorial takes Windows 8 X64 as a reference
brief description of the title:
The startup options that appear after Windows boot Manager--------installed Windows system (related information stored in NVRAM) can be deleted and established and BCDboot.exe related
Bootmgfw.efi--------boot files for booting Windows
Bootx64.efi---------required boot files for UEFI
BCDboot.exe--------Fix uefi boot command-line tool, Microsoft produced
introduce two concepts before you begin:
Computer Default boot-----------is whether your computer has an operating system, defined UEFI boot will boot your computer through Bootx64.efi, and into various modes, maintenance, installation, computer or system
Here is Bootx64.efi, which is just a generic name, rich in permissions and larger than Windows default, that is, if your Windows default startup file is gone,
Starting the computer's default boot file Bootx64.efi is also possible to start the computer. Use the computer default file to start your computer in a variety of environments at any time, EFI SHELL, ISO,
Windows, Linux ... Yes, all-in-all.
Windows default boot-------is if you have installed an operating system for your computer, or if you have fixed uefi boot, the boot menu will have the Windows boot Manager option, which starts the system from Bootmgfw.efi by default
Bootmgfw.efi the file for that location can only be used to start Windows, not a common name,Permissions Single
========================================================
0.
for UEFI boot environment, Bootx64.efi is more useful, here Bootx64.efi is a common name, that is, any valid EFI changed to Bootx64.efi is started by the computer to load and start.
Bootmgfw.efi is not a generic name and is only suitable for starting Windows.
Of course, for UEFI to start Windows, Bootx64.efi and Bootmgfw.efi are actually the same file, and the cyclic redundancy check CRC values are the same.
They all have the ability to start Windows, but they're not in the same position,
Efi\boot\bootx64.efi
Efi\microsoft\boot\bootmgfw.efi
The impact on the system's guidance is certainly not the same, let us verify ....
======================================================
From three directions: (The following conclusions are verified by the facts, can be any suspicion and speculation!!) ）
========================================================
1.CD Media uefi Boot "has been verified】：
By analyzing the UEFI boot record (efisys.bin) of a Microsoft original image, I found that the boot file for the original disc was efi\boot\Bootx64.efi, because this verification is simple, I have verified in total:
Win7 x64; win8 x86; the CD-ROM boot files of Win8 x64 areBootx64.efi Bootia32.efi Bootx64.efi
Conclusion:UEFI boot on CD-ROM is not dependent on the operating system and can be considered as a non-operating system environment, soBootx64.efiis aComputer DefaultBoot file========================================================
2.Mobile Disk media uefi Boot "has been verified】：
Universal that can be seen from the forum throughbootx64.efi start USB drive
Conclusion:UEFI on removable disk media boot is not dependent on the operating system, can be considered as a non-operating system environment, soBootx64.efiis aComputer DefaultBoot file
========================================================
3.Local Disk media uefi boothas been verified】：
:: Native ESP partition boot file analysis
I installed the operating system of Microsoft Win8 x64 to analyze all the files of the ESP partition,exist separately：
Efi\boot\bootx64.efi
Efi\microsoft\boot\bootmgfw.efi
We can't help thinking:which file tests are really used? Which does the computer start by default ? Which one does the system start by default ?
Well, it's easy, so let's just delete them and see if the system can start ....
1, delete bootmgfw.efi, keep bootx64.efi
> Results:
Select boot from local hard driveThe system can still boot into
Select Windows Boot Manager Enter failure
2, delete bootx64.efi, keep bootmgfw.efi
> Results:
Select boot from local hard driveEnter Failure
Selecting the Windows boot Manager system can still boot into
Conclusion:
Bootx64.efiIsComputer DefaultBoot file
Bootmgfw.efi isWindows defaultBoot file
4.connection between BCDboot and "Windows Boot Manager" "Bootmgfw.efi" "Bootx64.efi"
BCDboot fix System Boot command format: BCDboot system location/L language
Cases:
- BCDboot c:\windows/l ZH-CN
Copy Codewhen we execute the above code:
BCDboot.exe will fix the system boot and will fix theComputer Default bootAndWindows Default Boot, both Bootx64.efi and Bootmgfw.efi appear in the ESP partition,
and Bootx64.efi was renamed by Bootmgfw.efi. At the same time, a "Windows boot Manager" is generated from the Boot menu startup selection menu.
Windows Boot Manager and the information it contains are stored on the motherboardNVRAMInside, instead of saving on the hard disk, deleting Windows Boot Manager requires a deletion to the BIOS Settings area.
:: If we look at the BCD file through Bcdedit, we can find that Bootmgfw.efi is the Windows default boot file. So our conclusion is the same as the original ESP partition test.
in the UEFI specification, the positive solution about NVRAM:
NVRAM is an area of the BIOS ROM that is generally defined as 64k byte, and now EFI has all the variables present here.
Conclusion:
Bootx64.efiIsComputer DefaultBoot file
Bootmgfw.efi isWindows defaultBoot file
At last:
The main reason for writing this post is to be able to make those who are not very clear Bootx64.efi and bootmgfw.efi A distinguished or vague friend, a clear understanding of the relationship between the two and the difference do not have Bootx64.efi is Bootmgfw.efi renamed, Bootx64.efi is Bootmgfw.efi.
Like these incorrect statements to avoid misleading later friends .....
Exactly: "Bootx64.efi can be bootmgfw.efi, or it can be any other EFI program that works "
Other:
with the above verification you can know that uefi under repair Windows boot can be divided into: fix computer default boot and Windows default boot.
The more common is to repair the computer default boot , if you can be uefi under Manual/automatic repair computer default boot, then repair Windows default boot is also a cinch,
From the UEFI level, Windows is actually an EFI application of the computer, which is contained by the computer. So repairing the computer default boot is omnipotent .
Of course , BCDboot is useful when it is not manually repaired, and can be repaired under normal conditions. As long as your system is not overly streamlined, bcdboot should be able to handle it.
You can learn to fix it manually without worrying about it.
below is a manual repair of the computer default boot video tutorial, on the bottom of the first floor, the video looks very intuitive, a look to understand. after repairing the computer's default boot , we can boot Windows directly,
You can ignore the presence or correctness of Windows default boot.
"Perfect Edition" mount GPT disk for the ESP partition batch + Manual Repair uefi+gpt system Boot Screen tutorial
http://bbs.wuyou.net/forum.php?mod=viewthread&tid=300068&fromuid=396698
Some file references for computer default booting:
UEFI Boot Detailed: Start analysis +n operation instance, hurriedly come in study, do not lag behind, should give oneself to charge slightly ...
http://bbs.wuyou.net/forum.php?mod=viewthread&tid=299643&fromuid=396698 |
