Before the operating system starts loading, a specialized software computer initializes all components, checks their readiness for work, and only then transfers control to the OS loader.
Previously, a set of BIOS programs was used for these purposes, but this standard is now considered outdated, and it has been replaced by UEFI technology, which supports secure boot, has a pleasant graphical interface customization and many other benefits. Most modern motherboards and laptops come with UEFI. In this article, we will look at how linux installation on UEFI and what problems you may face.
This is an option for owners of UEFI boards who do not want to understand the intricacies of using this technology and agree to use their device as before with BIOS. Most motherboards allow emulation of BIOS mode. In this mode, you can install Linux without any problems and additional partitions, as it was done in the BIOS.
To enable Legasy BIOS mode, you need to enter the BIOS / UEFI settings using the F2, Del or Shift + F2 buttons and find the corresponding item there. For example, I have this item on the Boot tab. Here you need to select the boot mode UEFI or Legasy.
After saving the settings, you can install your operating system as usual. If this option does not suit you, then we will look at how to install Linux on UEFI.
Installing Linux on UEFI Boards
I will consider the installation using Ubuntu as an example, but all steps are the same for other distributions. First, you need to burn the disk image to a USB flash drive. Most distributions already support booting to UEFI.
Step 1. Burn Linux to UEFI USB stick in Linux
To write an image to a USB flash drive in Linux, it is better to use the Etcher utility. The program will write the media, which can be booted to both UEFI and a regular system. After starting the program, you need to select the system image:
Then the memory card and wait for the recording to complete:
You can also write the image to a USB flash drive manually. This is simpler than a regular BIOS, although it requires more steps. First, format your media to FAT32. This can be done in the standard Gnome disk management utility:
Then unzip the contents installation image to the root of the flash drive:
sudo mount /path/to/image.iso / mnt
sudo mount / dev / sdb1 / media / flash /
sudo cp -r / mnt / * / media / flash
Here / dev / sdb1 is the name of the partition of your flash drive. You can do all these steps in file manager... You don't have to use commands. Next, you need to install two flags on the flash drive partition where you unpacked your files - boot and lba. This can be done with Gparted. Just run the program, select your USB flash drive from the list of disks:
Click right click by section, select Manage flags and check the boxes against the boot and lba flags.
Whichever method you use, your flash drive is ready and you can boot from it. Most Linux images already contain an EFI bootloader and the computer's firmware will find it on the next reboot.
Step 1 (alternative). Writing Linux to UEFI stick on Windows
If you decide to burn Linux on Windows, then it is better to use the Rufus utility. It is necessary to set the following parameters in it:
- Partition scheme and system interface type: GPT for computers with UEFI;
- File system: FAT32.
All other parameters are default. After completing the recording, your USB stick is ready for use.
Step 2. Choosing the boot order
In order for your system to boot from the newly written flash drive, you need to disable UEFI Secure Boot... This mode allows only signed operating systems to boot, and only Microsoft operating systems are signed. Therefore, for Linux, this mode must be disabled. I also have this setting on the Boot tab:
In addition, you need to install the USB flash drive in the first place:
After that, you can restart your computer and proceed with the installation. If you have a window like this, then everything is fine. Here you need to select "Try Ubuntu without installing", this is a prerequisite:
I will not describe all the installation steps that need to be performed, they are no different from installing a regular OS, the only difference is in installing the bootloader and partitioning the disk. We will dwell on it further.
Step 3. Partitioning the disk for UEFI
UEFI has several differences from BIOS in this regard. The first is the use of a GPT disk partition table. it new technology, which has many advantages over MBR, including a very large number of primary partitions (there are only four in MBR), damage recovery, and much more. Read more about this in a separate article. The second difference is that the bootloader files are no longer stored in the first 512 bytes of the hard drive. They are all stored on a separate section called ESP.
Before you press "Install Ubuntu" it is advisable to prepare the disk using Gparted. Open the utility from the main menu of the image. Then select Device -\u003e Create Partition Table:
Select the GPT Partition Table from the list:
Step 4. Create the ESP section
In Gparted, we only need to create an ESP partition for UEFI. To do this, select "Unseen", then right-click on it and select "New":
Select FAT32 as the file system for the partition, size - 100 megabytes. Then press the button "Apply" to apply changes.
Then press "Manage Flags" and check the boxes next to the flags "boot" and "efi".
Step 5. Disk layout option
When the system prompts you to choose a marking method, you can let the system mark everything up automatically. But this is only if you do not already have any operating system installed. Otherwise, choose "Your own version":
Step 6. Assigning partitions
If you have chosen a different layout option, then a menu with a list of all sections will open in front of you. Find at the bottom of the window "Device for installing the bootloader" and select the EFI partition from the list.
Then click on the EFI partition in the list and select "EFI system partition":
Then you can proceed with the installation as usual. You need to create a root partition, and you can optionally create a bootloader, swap and home partition. You can read more about installing Ubuntu 18.04 at.
Step 7. Completing the installation
After all the files are unpacked and the bootloader is installed, the Linux installation on UEFI is complete, you can restart your computer and use your system as usual.
But let's take a closer look at managing menu items and EFI bootloaders.
Managing the UEFI bootloader with eifbootmgr
When the system boots up, you can display the default UEFI settings by running the command:
Let's take a closer look at what each of the parameters means:
- BootCurrent - the loader that was used to start this operating system;
- BootOrder - the order of loaders in which the boot manager will iterate over them during system startup. If the first bootloader fails, then the second one will be used, and so on;
- BootNext - a loader that will be launched at the next boot;
- Timeout - timeout during which the bootloader selection menu will be shown before it is automatically selected;
- Points 0000 - 0004 - loaders that can be used.
You can change the boot order using the -o option, for example, let's make the OS boot from the optical disk first:
sudo efibootmgr -o 0,1,2,3
And put Ubuntu back to first place:
sudo efibootmgr -o 3,0,1,2
You can change the timeout to display the system selection menu:
sudo efibootmgr -t 20
Here we have set the timeout to 20 seconds.
conclusions
In this article, we have covered how to install Linux on UEFI, as well as how to manage the boot order on the installed system. Now, if you have a desire to install this operating system on your new laptop with EFI, you already know how to do it. If you have any questions, ask in the comments!
So, you specified in the settings BIOS boot from CD / DVD or USB, and when booting from Ubuntu LiveCD, instead of a purple screen with keyboard and human icons, we got this screen:
It's okay, it happens. In this case, you need to take into account a number of points, which will be discussed in this section. By the way, the presence of a purple screen at boot does not mean at all that you do not have UEFI, just with a black screen all the UEFI features are most pronounced. So this section will be very helpful anyway. In the meantime, feel free to select the top line "Try Ubuntu without installing" and press Enter. After a short wait, you will be taken to the Ubuntu desktop, and while you wait for Ubuntu to load, let's talk about UEFI.
Introduction to UEFI and GPT
You may remember that one of the objectives of this guide is to teach the reader how to use all the basic tools of the system effectively and effortlessly. But for this you need to dig deeper and talk about the hardware stuffing of your computer, and how this stuffing works with the system. Therefore, again, a theory, you cannot do without it.
What happens when you turn on your computer? First of all, the computer must correctly initialize itself, that is, its own hardware, and transfer control to the operating system loader. This process is handled by the "Extensible Firmware Interface" ( EFI) (Extensible Firmware Interface) - the interface between operating system and firmware that controls low-level hardware functions. Previously, the BIOS was responsible for this, and now EFI, which, after another change in the standard, became known as the "Unified Extensible Firmware Interface" ( UEFI) is the name and will be used in the future. It should be noted that UEFI, as a more modern interface, fully supports all BIOS functions, the opposite, unfortunately, is not true. In the settings, the BIOS support mode is most often called "Legacy" ("inherited" or "traditional" in English) or simply "UEFI Disabled" ("UEFI is disabled", as you might guess). Now, however, we are interested in the enabled UEFI mode.
So, when you turn on the computer, UEFI starts to initialize the hardware and finds some kind of block device, say hDD... You probably know that the entire hard disk is almost never used - the disk is necessarily divided into partitions, including for ease of use. But to break it down into sections, you can, today, in two standard ways: using MBR or GPT... What is their difference?
MBR ("Master Boot Record" - the main boot recording) uses 32-bit identifiers for partitions, which are located in a very small piece of space (64 bytes) at the very beginning of the disk (at the end of the first sector of the disk). Because of this small footprint, only four primary partitions are supported (see this article for more details). Since 32-bit addressing is used, each partition can be no more than 2.2 TB. In addition, the boot record does not have any spare MBR, so if the application overwrites the master boot record, then all partition information will be lost.
GPT ("GUID Partition table" - table partitions GUID) already uses 64-bit identifiers for partitions, so the piece of space in which information about partitions is stored is already more than 512 bytes, in addition, there is no limit on the number of partitions. Note that the partition size limit in this case is almost 9.4 ZB (yes, you read that correctly - zettabyte, one with twenty one zeros!). And at the end of the disk there is a copy of the GPT that can be used to repair the damaged main partition table at the beginning of the disk.
So, when communication between the hardware and the operating system is carried out through the enabled UEFI mode (and not Legacy BIOS), using GPT for partitioning partitions is practically compulsoryotherwise, there will likely be compatibility issues with the MBR.
Well, it seems that we figured out the block devices, UEFI initialized everything correctly, and now it must find the operating system loader and transfer control to it. As a first approximation, it looks like this: since UEFI is the successor to BIOS, it searches for a bootloader in strict accordance with the established rules. If it finds an operating system bootloader that does not support UEFI, then BIOS emulation mode is activated (this is exactly the case, even if the Legacy BIOS is not explicitly specified). And everything starts all over again, with the only difference that now emulated The BIOS checks the health of the hardware and loads the firmware — simple drivers for individual hardware components. After that emulated The BIOS again searches for the OS bootloader and activates it. That, in turn, loads the operating system or displays a list of available operating systems.
And in the case of UEFI, everything happens a little differently. The fact is that UEFI has its own operating system loader with integrated launch managers for the installed OS. To this end, for it - for the UEFI bootloader - a small partition (100-250 MB) must be created on the disk, which is called "Extensible Firmware Interface System Partition" (system partition of the extensible firmware interface, ESP). In addition to the specified size, the partition must be formatted in the FAT32 file system and be bootable. It contains drivers for hardware components that can be accessed by a running operating system. And in this case, the download happens directly from this section, which is much faster.
So, let's summarize: in order to fully use the UEFI functionality, the disk must be with GPT, and it must have a special ESP partition. Pay attention to the phrase “to complete use the functionality "- there are many ways to install Ubuntu on a system with UEFI" stripped down "to one degree or another, and they all depend on the presence or absence of preinstalled operating systems on your computer. For example, you want to keep Windows preinstalled. Which Windows - the "seven" or the newfangled 8.1? Or maybe, God forbid, you have installed "Peratskaya Windows", activated with MBR, and does not want to start with GPT, and you, nevertheless, want to study it further? In addition, a lot depends on the bitness of operating systems - without dancing with a tambourine, it is impossible to make a 32-bit system work with UEFI. And there are many such examples. Therefore, in this section, we will only talk about installing Ubuntu in the "maximum full" mode of using UEFI capabilities, although even after reading this introduction, you can already imagine the device of your computer and, if you wish, implement your own installation script.
Well, let's get started?
Disk layout
So you've booted into Ubuntu from a LiveCD in UEFI mode. Open the "GParted Partition Editor", for now let's talk about some very important features that you need to pay attention to.
Most importantly, you should have a plan of your actions, believe me - the list of steps and the order of their implementation is quite extensive, so it is advisable to write down the main points of the plan somewhere on a piece of paper and check them periodically. So what do you know. For a normal Ubuntu installation in UEFI mode, your computer's hard drive must be properly prepared, namely:
The disk must be with GPT;
The disk must have a special ESP section;
The disk should have standard partitions: system, swap, and a partition for the home directory.
In addition, you need to decide on the operating systems on your computer - the partition and installation plan depends on whether Ubuntu will be the only system, or there will be other systems that support UEFI mode next to it.
Let's start by answering the second question: about the availability of other operating systems. If your computer already has operating systems that support booting in UEFI mode (for example, Windows 8), and you do not intend to abandon them yet, then the first two points of the plan have already been completed: the ESP section probably already exists, and the disk, of course, with GPT. Let's check that this is indeed the case.
Suppose, after launching the GParted Partition Editor, you will see the following window:
What information can you get from a careful study of this window? First, take a look at the "File System" column: all partitions are formatted in ntfs, except for one partition with the fat32 file system, which appears to be the ESP partition. Windows 8 is already installed on the disk (the / dev / sda4 partition - in Windows this is drive C :) - this is indicated by label disk (column "Label"). Secondly, there are a number of Windows service partitions on the hard disk - you can find out about this not only by the labels (WINRE_DRV and LRS_ESP), but also by flags (column "Flags") - all these sections are hidden, because they have the hidden flag set, which hints at the special nature of the information on them. Finally, take a closer look at the / dev / sda5 partition - have you accidentally lost your D: drive on Windows? Here he is, safe and sound.
So, the first two points of the plan have already been completed, and the implementation of the third point: creating partitions for Ubuntu is described in sufficient detail in the example of using GParted to repartition a hard disk. Let us briefly recall that from the data disk (in the example it is / dev / sda5, or the D: drive in Windows), you need to "cut off" enough space and in its place create three partitions: swap, system and the partition for the home directory. Also note that your disk is GPT, so an extended partition containing logical drives, it does not, therefore, when creating partitions, choose Primary partition ("Main Section").
Do not perform any operations with Windows service partitions - they are designed for the normal functioning of this OS. Accidental or deliberate modification of these sections is guaranteed to lead to problems in Windows, up to and including its complete inoperability.
As a result, you should get something similar to this picture:
The additionally created sections are shown here:
Please write down the purpose of the sections. In the example shown:
/ dev / sda2 - EFI section (ESP)
/ dev / sda6 - system partition (partition for the "root" of the system)
/ dev / sda7 - swap partition
/ dev / sda8 - section for user data.
This information will be very useful in the future when installing Ubuntubecause the large number of partitions makes it very easy to get confused and assign the desired mount point to the wrong "digit".
Nevertheless, we continue to work with the GParted editor. Your task is to delete all partitions and create the necessary disk configuration for Ubuntu in the free space. To do this, you can right-click on each of the sections and select "Delete" from the drop-down menu. But it's better to do it differently: find the "Device" item on the menu bar of the GParted editor and select "Create Partition Table ..." from the menu. A warning will appear:
WARNING: This will ERASE ALL DATA on the ENTIRE DISK / dev / sda
(WARNING: this will DELETE ALL DATA on ALL DISK / dev / sda)
Don't worry, you took care of your backups, right? Look a little below - at the inscription "Advanced" (Details). Click on the triangle on the left and select gpt from the menu:
All disk space will be grayed out. Right click on it and start creating the required partitions by choosing “New” from the drop down menu. The first of the new partitions is a special ESP partition that is required, as you remember, for UEFI to work. Since it is formatted in a non-Linux file system, and in addition, it must be bootable, then it must be located at the beginning of the disk space. Give it a size in the "New size (MiB)" field of 100 MB and a file system fat32:
In the same way, create partitions for the future: system (15 GB with ext4 file system), swap partition (4 GB with linux-swap) and for the home directory (all remaining space in ext4). As you remember, GParted does not apply changes immediately, but simply queues them up for execution. So click on the green “Apply All Operations” checkbox:
Yes, it is not at all necessary to control the boot flags at this stage - the Ubuntu installer will do everything as it should. Now read carefully about how to install Ubuntu, and when you're ready, let's move on.
Installing Ubuntu
After all this preparatory work, the installation of Ubuntu should be straightforward, especially if you read the installation rules carefully. Just take out a piece of paper with a list of partitions and note that for a special EFI partition (/ dev / sda2 from the example about installing Ubuntu and Windows together), you need to precisely assign the property eFI boot partitionand not the BIOS backup boot area:
If you don't, the installer will show you the following notification:
Correct the error, and if it does not work, exit the installer, start the GParted editor and check that everything described above is completed.
The assignments for all other partitions required when installing Ubuntu are described in great detail in this section, so there is little point in dwelling on this in more detail.
Possible problems
Sometimes it happens that after installation, one of the operating systems preinstalled on the computer does not start. Well, without going into rather complex ways of bringing everything back to normal, we note that there is a comprehensive solution possible problems with loading. The name of this solution is Boot-repair .
This little program is very powerful tool, which allows you to fix almost all errors that can occur when booting Ubuntu and other operating systems after installation.
Stick to the golden rule: “ Never fix something that hasn't broken yet»!
Boot into Ubuntu. It doesn't matter how you do it - Boot-Repair works on both the LiveCD and the installed system. Of course, if you are having difficulty booting your newly installed Ubuntu, then the first option is the only one. First, you need to install Boot-Repair on your computer, this is done using the terminal. Press Ctrl + Alt + T and in the window that appears, type:
: Change the team closer to the release.
Sudo add-apt-repository "deb http://ppa.launchpad.net/yannubuntu/boot-repair/ubuntu saucy main"
Now, of course, you will say: “What are you there, at all? So many letters - I don't understand anything and I will definitely be mistaken! " Of course, no one spells the presented command into the terminal - just select it completely and click the middle mouse button in the terminal window, or drag the selected text there. Hit Enter. If you are on Ubuntu already installed, you will be prompted to enter your password. Please note that when you enter the password, no characters are displayed: no dots, no asterisks - nothing at all - probably there is no need to explain why this is done. After entering the password, press Enter again.
Download the public key of the repository with the program from the trusted key store:
Sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 60D8DA0B
Update the list of applications with the command:
Sudo apt-get update
Install and run Boot-Repair:
Sudo apt-get install -y boot-repair && (boot-repair &)
After a short scan, the main Boot-Repair window will appear:
: In the process of writing.
As soon as we turn on the computer, it immediately starts running a miniature operating system that we know as BIOS. She is engaged in testing devices, memory, loading operating systems, allocating hardware resources. Many of the features in this suite of programs (typically around 256-512 KB) support older operating systems like MS-DOS, giving them many options. Since the days of the PC / AT-8086, the BIOS has changed very little, and by the time the first Pentiums were launched, its development had almost stopped. Actually, there was nothing to change in it, except for a dual BIOS, support for network facilities and the possibility of flashing. But there are many drawbacks: starting entry into the real mode of the processor, 16-bit addressing and 1 MB of available memory, the inability to have a "repair" console. And of course the everlasting support problem hard drives... Even now, drives up to 2.2 TB are guaranteed to be supported, no more.
Back in 2005, Intel decided to change the BIOS to EFI / UEFI (Unified Extensible Firmware Interface). The EFI system is a more advanced base operating system. On some Unix and Windows platforms, UEFI has been around for a long time, but a massive transition has yet to take place, despite good intentions. And they are as follows:
- The presence of the notorious console for repairing system parameters and installing the OS;
- The EFI section makes it possible to perform some actions without booting the OS (watching movies, starting music);
- Internet access and therefore availability installed drivers network, TCP / IP stack, etc.);
- Presence graphics mode and custom scripts;
- Support for giant disks;
- Storing UEFI on new format (GPT) partitions;
- Full support for all hardware from the start.
UEFI can use a general-purpose runtime machine like the JVM to use hardware-independent code, which opens up huge horizons for creating "bootable" software.
There is also criticism of this technology. In particular, its implementation can lead to cutting off new players from the operating system market: there will always be some kind of technological loophole in the code for this. Like, for example, the inability to boot Windows 98 from modern BIOS. Worse, you have to forget about the millions of MS-DOS programs and other systems that relied on BIOS functions to operate. Perhaps they will still be emulated, but there are doubts about that. And among them there are probably important programs that there will be no one to rewrite. However, all these are solvable issues - at least due to virtual operating systems. But the fact that new types of viruses will appear is for sure, and we will be able to see it pretty soon.
Hello! Windows 8.1 does not boot on a laptop with UEFI BIOS and I can't do anything. When loading, an error appears on the File: \\ EFI \\ Microsoft \\ Boot \\ BCD screen ... I studied all the Internet articles on this topic, but in my case nothing helps.
What has been undertaken by me!
- Loaded with installation disk Windows 8.1 and searched for the installed operating system with the command bootrec / RebuildBcd, an error occurred " Scanning installed systems Windows completed successfully. Total Windows systems detected: 0»
- Deleted partition (300 MB), encrypted (EFI) system partition containing all files windows bootloader 8.1 team del vol, then applied Automatic Boot Repair, the system recreates this partition, but does not boot. Making this section active on the command line didn't help either.
- Also formatted the same partition (300 MB), Encrypted (EFI) with the command format fs \u003d FAT3 and recreated it.
- Tried writing a new boot store for Windows 8.1 with the command bcdboot.exe C: \\ Windows, where (C :) is the partition with the operating system installed windows system 8.1 and I get an error againFailed to copy download files.
I entered commands that are successful, but Windows does not boot.
bootrec / FixMbr
bootrec / FixBoot
I don't know what else to do and how to restore the Windows 8.1 bootloader. Can you tell me?
Hello friends! My name is Vladimir and I will answer this question.
If your Windows 8.1 does not boot and you used all the available tools to restore the boot loader, then you can delete the responsible for booting the system: the encrypted (EFI) system partition 300 MB, as well as the MSR partition 128 MB and recreate them.
In Disk Management, you can only see encrypted (EFI) system partition 300 MB, MSR partition 128 MB visible only on the command line when entering a command "Lis par".
Note: If you do not have experience, do not perform this operation unnecessarily, use first the other methods from section about. If you want to experiment on a working laptop, then do not start work without first creating backup of these sections, and best of all create.
We will delete and recreate partitions:
1. Section (400 MB) containing the Windows 8.1 recovery environment (you can completely get rid of this section and use, if necessary, the recovery environment located on the bootable media with Win 8.1).
2. Section (300 MB), an encrypted (EFI) system partition containing all the Windows 8.1 boot loader files.
3. MSR service section ( Microsoft System Reserved) 128 MB, required for partitioning GPT disks.
We boot the laptop from and in the initial window of the system installation press the keyboard shortcut Shift + F10,
a command line window opens, enter the commands:
diskpart
lis dis (lists physical disks).
sel dis 0 (select the laptop hard drive 931 GB, and the second 14 GB drive - bootable uSB flash drive 8.1).
lis par (showing all partitions of the selected disk, the first three partitions will be deleted).
sel par 1 (select the first section
del par override (delete the partition, to delete the ESP and MSR partition or the laptop OEM partition, you must specify the override parameter)
sel par 2
del par override
sel par 3
del par override
That's it, we have deleted all three hidden sections.
Now, if you select a disk and enter the lis par command, then we will see only two partitions on the laptop hard disk:
Section 4 - Windows 8.1 Installed
Section 5 - hidden section restore with factory settings.
Create a re-encrypted (EFI) 300 MB system partition, as well as a 128 MB MSR partition
We enter the commands:
diskpart
lis dis (display a list of disks).
sel dis 0 (select laptop hard drive).
create par efi size \u003d 300 (create an encrypted (EFI) system partition 300 MB).
format fs \u003d fat32 (format it to FAT32 file system).
creat par msr size \u003d 128 (create a 128 MB MSR partition)
How to repair EFI bootloader Windows 7 and Windows 10?
In this article, we will try to restore the EFI bootloader for Windows 7 /8 /10 ... We have already analyzed a little earlier. For now, let me immediately note that damage to the bootloader in our case is most often (among other things) caused by:
- installing a second operating system
- incorrect operations to restore the system (or unsuccessful completion)
- deleting some data from hidden sections
- broken sectors
- by the action of malware.
Using the presented tools, you can try to restore the bootloader EFIwhich refuses to boot the system due to a missing or broken configuration file at:
Hidden Drive: \\ EFI \\ Microsoft \\ Boot \\ BCD
By the way, here is its approximate content from:
To make it clear ...
The partition structure in a GPT table on Windows loaded in UEFI mode most often looks like this:
- EFI - ESP section ( Extensible Firmware Interface) - the section where the software with the drivers for loading Windows is stored;
- MSR - he is Microsoft Reserved - redundant during installation Windows partition; it may not be on your machine
- Primary section - where system files are stored: registry, services, system utilities, settings files, etc.
Windows 10 also adds a disk here Recovery... By default (i.e. when windows installation to a UNFORMATED disk), the first two partitions have a clear size. And therefore, if necessary, it is easy to isolate them, focusing only on the size of both. In Windows 7, for example, this is respectively 100 Mb and 128 MB... And this, as they say, is a typical configuration. Some computer manufacturers create partitions as they see fit, for example by sticking Windows PE recovery environment into a file. winre.wim... If you find such a file in yourself, know that it is it that contains the system recovery image from the manufacturer. Section EFI required on GPT disks with UEFI support. When the computer turns on, the UEFI environment loads the bootloader ( EFI \\ Microsoft \\ Boot \\ bootmgfw.efi) from section EFI (ESP), transferring control over the boot to Windows itself. No partition - no download.
Section same MSR on the disk is created to facilitate the overview of partitions and is used for system operations (such as converting a disk from simple to dynamic). This is a fallback partition that Windows never assigns an identifier to. And it does not contain user data. In Windows 10, the size of the MSR partition is 16 Mb (in Windows 8 - 128 MB), file system type - NTFS.
Windows Boot Configuration Data
That the file at the above address EFI \\ Microsoft \\ Boot \\ BCD damaged, you can be informed blue screen death BSOD with the following error:
The boot configuration data for your PC is missing or contains errors. File: \\ EFI \\ Microsoft \\ Boot \\ BCD Error code: 0xc0000 ***
This means that the data in the file Boot Configuration Data do not recognize your Windows bootloader configuration. However, users familiar with the MFT bootloader repair utility bcdedit.exe, this time it won't help out. When trying to run it, the user will see something unusual:
The boot configuration data store could not be found. The requested system device cannot be found
They say that neither the data nor the device itself exists. There is only one reason: since the BCD bootloader configuration in UEFI boot mode lies in a special EFI partition:
efi partition in Windows 7
efi partition in Windows 10
... then our utility simply does not see it. Those. does not see the bootloader itself, or even the entire section. In general, traditional recovery tools created for such a case do not save either:
You also misspelled it?
How to repair the EFI bootloader Windows 10: forehead.
- choose boot deviceby calling up the fastboot menu with the keys in zone F or
- load from;
- exit to the command line by holding Shift + F10 after the window appears Installing Windows
- as in the previous mode, we need to decide on the list of computer partitions. Further, I will assume that the hard disk is installed in a single copy:
- find the EFI partition. Its size, I repeat, is small ( 100 Mb in W7 and W10) and it has the FAT32 file system:
my EFI is an unnamed Volume 3
- it is hidden by default, which means it has no letter. For further work we need it. So we assign a letter right now:
After closing the program, we go to this section:
cd / d Y: \\ EFI \\ Microsoft \\ Boot \\There is a slight digression here. This path exists by default, and there is no reason for the console to refuse you to go to the specified folder. If an error appears, see paragraph Possible mistakes or go directly to the next part How to repair the EFI bootloader Windows 7/10: rebuilding the EFI.
i got an error Denied access immediately
- re-create the boot sector of the partition of the same name:
- using utility bcdedit.exe create the repository again by copying boot files of system folder:
/ f ALL - copy boot files (both UEFI and BIOS modes) for possible boot support on EFI and BIOS;
/ l ru– ru - will indicate the language locale of the system that will be used, i.e. into Russian. If everything goes well, skip this paragraph.
- we execute the following commands sequentially:
Reboot to Windows 10 on your hard drive and check.
Possible mistakes
Some errors may lie in wait for the administrator here. Among them, the most common are:
- BFSVC Error: Can not open the BCD template store. status - -
you need to check the entered commands and the path to the storage of Windows system files; sometimes the error appears due to the incorrect indication of the language locale; - BFSVC Error: Error copying boot files from Last Error \u003d 0x570 - the error is a consequence of the very phenomenon that Windows does not boot. It is likely that bad sectors appeared not only in the EFI boot section, but also on the system disk; drive the hard disk with the utility chkdsk.exe right there from the console with the command
where c is the disk with the system
- Access denied - there are many reasons for that: from the presence of bad sectors to an incorrectly set boot mode (worth Legacy instead UEFI; need to - uEFI only) from a flash drive. However. UEFI would not be UEFI if everything went so smoothly: the fact that the EFI partition does not admit its files is more a pattern than an exception. So, if access is denied to you, I advise you to simply delete the EFI partition itself (and we no longer need it), recreate it with the only directory necessary for it to work, and then rely on the repair bootrecallowing her to complete the job. So, if the need arose, we continue to work from the moment the team refused.
How to repair the EFI bootloader Windows 7/10: rebuilding EFI.
The most important thing here is not to miss the section / lami and do not delete the one in which the windows data and your information. So once bootrec.exe I could not get into the section we need, we remove the section. To do this, we will need to go back to diskpart.exe, again determine the partitions and select the one that is 100 MB. We return to the repair console:
Cd / d x:
And we start over:
Diskpart select disk 0 list partition select partition 2
remove it:
Delete partition override
you can check the result:
List partition
We have some unallocated space left in which we re-create the just deleted partition:
Create partition efi size \u003d 100 list partition select partition 1 format quick fs \u003d fat32 label \u003d "System" 
But when you try to assign the previously used letter Y, the console refused (it had to be restarted). I will assign a letter to the section Z:
Assign letter \u003d Z exit
Let's prepare the ground for bootrec.
- create a download folder:
- copy the files there from the EFI environment from the folder installed Windows (C is the letter of the drive with Windows system files):
- let bootrec from your flash drive will check the disks for Windows system files:
They will not go anywhere unless you accidentally deleted them, or they did not fall into the zone of bad sectors. It remains ...
- ... force to write the "correct" BCD file and other "configs":
Turn off the computer, take out the flash drive and turn on the machine. We wait the advent of Windows... Let it boot to the Desktop and check if everything is in place.
The error reappears ...
Do not worry. If you delved into the process, and entered all commands deliberately and correctly, the situation is most likely already fixed. You just need to take into account the peculiarities of the security filters adopted for the UEFI mode, and do not confuse the drive letters. They can be passed by following these steps:
- Wake up BIOS:
- remove the cover on the side of the computer or the bottom of the laptop
- disconnect the hard drive (by disconnecting both loops on the "hospital" or removing them from the connectors on the laptop)
- turn on the machine, waiting for the download error;
- after turning off the computer, reconnect the hard drive and again, turning on the computer, check; - check the UEFI menu of the computer board for the correct order of the boot partitions; the first should be, as you understand, EFI;
- make sure the label Bootable stands only opposite the EFI partition, and no one else. Unfortunately, it will not work to check and correct the situation from Windows PE. And for this you have to use additional tools in the form of a bootable USB drive. Do it any convenient option from the article Disk Label Bootable: how to add or remove?
That's all I wanted to say. Good luck.
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