Dual boot windows linux grub

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Привет, Хабр! Сегодня мы рассмотрим ситуацию, когда при двойной установке Linux & Windows загрузчик GRUB не стартует, давая возможность выбрать ОС, а автоматически загружается Windows. Немного теории:

GRUB (GRand Unified Bootloader) — программа-загрузчик операционных систем.
GRUB может загрузить любую совместимую с ней операционную систему. Среди них: Linux, FreeBSD, Solaris и многие другие. Кроме того, GRUB умеет по цепочке передавать управление другому загрузчику, что позволяет ему загружать Windows (через загрузчик NTLDR), MS-DOS, OS/2 и другие системы.

Значит с теорией мы немного разобрались (думаю этого будет достаточно), теперь же рассмотрим, какие бывают подводные камни, при установке Dual Boot Windows и Linux на одном компьютере.

Эксперимент производился на рабочей станции со следующими характеристиками:

Base Board Information

• Manufacturer: Acer
• Product Name: Aspire XC600

Memory Device

• Size: 4096 MB
• Type: DDR3
• Speed: 1333 MHz
• Manufacturer: Kingston
• Rank: 2

HDD

• product: ST500DM002-1BD14
• vendor: Seagate
• physical id: 0.0.0
• bus info: scsi@0:0.0.0
• logical name: /dev/sda
• size: 465GiB (500GB)
• capabilities: gpt-1.00 partitioned partitioned:gpt

Доказано, что проблем с установкой Debian 8.6 Jessie совместно с Windows 10 не обнаружено. Debian корректно прописывается в автозагрузке, GRUB запускается без ошибок и две ОС также работают нормально.

Но, как показала практика, не со всеми дистрибутивами такое происходит. При установке Ubuntu 16.04.1 вместо Debian на ту же рабочую станцию вылез первый подводный камень — GRUB не стартовал, и Windows 10 автоматом шла на загрузку.

Решение проблемы было найдено спустя недели три-четыре (тогда уже надоело считать, сколько времени убито на решение проблемы). Оно оказалось неожиданным, но в тоже время вся система заработала. Значит, если вы столкнулись с такой же проблемой, приведенная ниже инструкция может вам пригодится и сэкономить кучу времени.

Важно! До начала выполнения инструкции нужно подготовить LiveCD с дистрибутивом Linux Mint — все операции мы будем выполнять на нем (я выбрал этот дистрибутив из-за того, что на него спокойно можно установить Midnight Commander, что сложно сделать на LiveCD с Ubuntu, так мы получаем больше пространства для маневров). Также стоит заметить, что команда из под консоли update-grub вам не поможет, так как она рассчитана на случай, когда GRUB запускается, но не видит другие ОС кроме Линукса. Также рекомендую создавать резервные копии файлов/каталогов, над которыми вы осуществляете хоть малейшие изменения.

1. Через терминал, с правами root смонтировать раздел с EFI в папку /mnt. В моем случае, это была команда mount /dev/sda2 /mnt.
2. Введите команду sudo -s и подтвердите пароль (он пустой по умолчанию) для последующих операций (многие советуют не делать этого, а вводить sudo и команду для выполнения — я поддерживаю это мнение, но инструкция рассчитана на опытных пользователей системы Linux, которые понимаю, что делают все на свой страх и риск).
3. Запустить Midnight Commander командой mc.
4. Найти в файловой системе следующий каталог: EFI в папке /mnt.
5. Переименовать каталог Microsoft во что-нибудь другое, например в Microsoft2.
6. Создаем новый каталог с именем Microsoft.
7. Заходим в только что созданный каталог Microsoft и частично создаем внутри его иерархию папок аналогичную старому Microsoft (тому, что переименовали). В моем случае он имел такую структуру папок: /boot/, затем куча папок и файл bootmgfw.efi рядом с ними. Нужно воссоздать структуру папок ровно до этого файла. Т.е. всё, что лежит рядом с ним — не нужно, а всё, что идет до него (т.е. родительские папки, соседние с ними тоже не нужны) воссоздаем в нашей новой папке Microsoft. В моем случае понадобилось создать только папку /boot, итоговый путь до нового каталога вышел таким: /EFI/Microsoft/boot. Можно просто скопировать все папки и файлы — проверено, это работает и можно не создавать все вручную.
8. Находим в каталоге из шага 6 папку с именем нашего дистрибутива Линукса, в нашем случае это Ubuntu. Копируем (оригиналы файлов и папку ubuntu на всякий случай оставляем, не помешают) все файлы из данной в папки в итоговый каталог, созданный на предыдущем шаге: /EFI/Microsoft/boot.
9. В получившейся файловой системе находим файл grubx.efi или grubx64.efi (будет только один из них: в зависимости от разрядности установленного Линукса). Переименовываем его в bootmgfw.efi.
10. Находим файл /boot/grub/grub.cfg в файловой системе установленного Линукса. Открываем его для редактирования. Внутри него находим слово «Microsoft» в контексте строки, начинающейся с «chainloader» и заменяем это слово (должно быть только одно вхождение и именно в строке с «chainloader», так что не ошибетесь) на название каталога, в который мы переименовали Microsoft (т.е. на Microsoft2 в нашем примере). Сохраняем изменения в файле.

Также, в этом файле вы можете поменять названия в списке, который выводит GRUB. Например, вместо

openSUSE Leap 42.2 27.01

в части кода:

menuentry 'openSUSE Leap 42.2 27.01'  --class opensuse --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-996b3ed5-150f-4de3-a40c-6d385e27d6de' {
	load_video
	set gfxpayload=keep
	insmod gzio
	insmod part_gpt
	insmod ext2
	set root='hd0,gpt6'
	if [ x$feature_platform_search_hint = xy ]; then
	  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt6 --hint-efi=hd0,gpt6 --hint-baremetal=ahci0,gpt6  996b3ed5-150f-4de3-a40c-6d385e27d6de
	else
	  search --no-floppy --fs-uuid --set=root 996b3ed5-150f-4de3-a40c-6d385e27d6de
	fi
	echo	'Загружается Linux 4.4.36-8-default …'
	linuxefi /boot/vmlinuz-4.4.36-8-default root=UUID=996b3ed5-150f-4de3-a40c-6d385e27d6de ro  resume=/dev/sda7 splash=silent quiet showopts
	echo	'Загружается начальный виртуальный диск …'
	initrdefi /boot/initrd-4.4.36-8-default
}

Написать

openSUSE The best choice!:)

:

menuentry 'openSUSE The best choice!:)'  --class opensuse --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-996b3ed5-150f-4de3-a40c-6d385e27d6de' {
	load_video
	set gfxpayload=keep
	insmod gzio
	insmod part_gpt
	insmod ext2
	set root='hd0,gpt6'
	if [ x$feature_platform_search_hint = xy ]; then
	  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt6 --hint-efi=hd0,gpt6 --hint-baremetal=ahci0,gpt6  996b3ed5-150f-4de3-a40c-6d385e27d6de
	else
	  search --no-floppy --fs-uuid --set=root 996b3ed5-150f-4de3-a40c-6d385e27d6de
	fi
	echo	'Загружается Linux 4.4.36-8-default …'
	linuxefi /boot/vmlinuz-4.4.36-8-default root=UUID=996b3ed5-150f-4de3-a40c-6d385e27d6de ro  resume=/dev/sda7 splash=silent quiet showopts
	echo	'Загружается начальный виртуальный диск …'
	initrdefi /boot/initrd-4.4.36-8-default
}

Хоть мелочь, а приятно! Остальное в коде советую не трогать.

Если трудно разобраться с управлением Midnight Commander (в этом нет ничего страшного, у меня тоже в первый раз были проблемы с этой программой), все операции можно выполнить в файловом менеджере Nautilus (или в другом, не суть важно), но изначально запустив его под правами пользователя root.

После этого идем на перезагрузку и радуемся результату. Но, как оказывается, такая проблема есть и у дистрибутива OpenSUSE Leap 42.2. Как показала практика, если на компьютере установлен дистрибутив OpenSUSE с Windows 10, то приведенная выше инструкция не поможет. Точнее, она поможет, но только ее нужно дополнить. После выполнения основной части выполняем следующие шаги:

1. После выполнения всех операций заходим в папку /EFI/opensuse/x86_64-efi/ (название итоговой папки x86_64-efi может быть другим в зависимости от архитектуры ПК)
2. Копируем файл grub.efi (если у вас включена опция Secure Boot, там будет еще файл shim.efi, тогда советую скопировать их вместе)
3. Заходим в папку /EFI/Boot и удаляем все файлы, которые там есть (при обновлении загрузчика они снова появятся, но в этом нет ничего страшного)
4. Вставляем файл (или файлы), которые мы скопировали и спокойно идем на перезагрузку.
   Вот и вся инструкция. Думаю, кому-то пригодится…

P.S. Если же у вас все хорошо, GRUB с OpenSUSE запускается, но не видит Windows, радуйтесь — проблема решается всего одной командной: grub2-mkconfig -o /boot/grub2/grub.cfg, а если у вас стоит Ubuntu, нужно выполнить просто update-grub.

Для тех же, кого заинтересовала данная тема, рекомендую прочитать статью: «Начальный загрузчик GRUB 2 — полное руководство».

This is an article detailing different methods of Arch/Windows coexistence.

Important information

Windows UEFI vs BIOS limitations

Microsoft imposes limitations on which firmware boot mode and partitioning style can be supported based on the version of Windows used:

Note: The following points only list configurations supported by the Windows Setup even though Windows itself may still work on these unsupported configurations. A good example of this is Windows 11 which still works on a BIOS/MBR configuration once the Windows Setup check is bypassed.

• Windows 8/8.1 and 10 x86 32-bit support booting in IA32 UEFI mode from GPT disk only, OR in BIOS mode from MBR disk only. They do not support x86_64 UEFI boot from GPT/MBR disk, x86_64 UEFI boot from MBR disk, or BIOS boot from GPT disk. On market, the only systems known to ship with IA32 (U)EFI are some old Intel Macs (pre-2010 models?) and Intel Atom System-on-Chip (Clover trail and Bay Trail) Windows Tablets, which boot ONLY in IA32 UEFI mode and ONLY from GPT disk.
• Windows 8/8.1 and 10 x86_64 versions support booting in x86_64 UEFI mode from GPT disk only, OR in BIOS mode from MBR disk only. They do not support IA32 UEFI boot, x86_64 UEFI boot from MBR disk, or BIOS boot from GPT disk.
• Windows 11 only supports x86_64 and a boot in UEFI mode from GPT disk.

In case of pre-installed Systems:

• All systems pre-installed with Windows XP, Vista or 7 32-bit, irrespective of Service Pack level, bitness, edition (SKU) or presence of UEFI support in firmware, boot in BIOS/MBR mode by default.
• MOST of the systems pre-installed with Windows 7 x86_64, irrespective of Service Pack level, bitness or edition (SKU), boot in BIOS/MBR mode by default. Very few late systems pre-installed with Windows 7 are known to boot in x86_64 UEFI/GPT mode by default.
• ALL systems pre-installed with Windows 8/8.1, 10 and 11 boot in UEFI/GPT mode. Up to Windows 10, the firmware bitness matches the bitness of Windows, ie. x86_64 Windows boot in x86_64 UEFI mode and 32-bit Windows boot in IA32 UEFI mode.

The best way to detect the boot mode of Windows is to do the following[1]:

• Boot into Windows
• Press Win+R keys to start the Run dialog
• In the Run dialog type msinfo32.exe and press Enter
• In the System Information windows, select System Summary on the left and check the value of BIOS mode item on the right
• If the value is UEFI, Windows boots in UEFI/GPT mode. If the value is Legacy, Windows boots in BIOS/MBR mode.

In general, Windows forces type of partitioning depending on the firmware mode used, i.e. if Windows is booted in UEFI mode, it can be installed only to a GPT disk. If Windows is booted in Legacy BIOS mode, it can be installed only to an MBR disk. This is a limitation enforced by Windows Setup, and as of April 2014 there is no officially (Microsoft) supported way of installing Windows in UEFI/MBR or BIOS/GPT configuration. Thus Windows only supports either UEFI/GPT boot or BIOS/MBR configuration.

Tip: Windows 10 version 1703 and newer supports converting from BIOS/MBR to UEFI/GPT using MBR2GPT.EXE.

Such a limitation is not enforced by the Linux kernel, but can depend on which boot loader is used and/or how the boot loader is configured. The Windows limitation should be considered if the user wishes to boot Windows and Linux from the same disk, since installation procedure of boot loader depends on the firmware type and disk partitioning configuration. In case where Windows and Linux dual boot from the same disk, it is advisable to follow the method used by Windows, ie. either go for UEFI/GPT boot or BIOS/MBR boot. See https://support.microsoft.com/kb/2581408 for more information.

Install media limitations

Intel Atom System-on-Chip Tablets (Clover trail and Bay Trail) provide only IA32 UEFI firmware without Legacy BIOS (CSM) support (unlike most of the x86_64 UEFI systems), due to Microsoft Connected Standby Guidelines for OEMs. Due to lack of Legacy BIOS support in these systems, and the lack of 32-bit UEFI boot in Arch Official Install ISO (FS#53182), the official install media cannot boot on these systems. See Unified Extensible Firmware Interface#UEFI firmware bitness for more information and available workarounds.

Bootloader UEFI vs BIOS limitations

Most of the linux bootloaders installed for one firmware type cannot launch or chainload bootloaders of the other firmware type. That is, if Arch is installed in UEFI/GPT or UEFI/MBR mode in one disk and Windows is installed in BIOS/MBR mode in another disk, the UEFI bootloader used by Arch cannot chainload the BIOS installed Windows in the other disk. Similarly if Arch is installed in BIOS/MBR or BIOS/GPT mode in one disk and Windows is installed in UEFI/GPT in another disk , the BIOS bootloader used by Arch cannot chainload UEFI installed Windows in the other disk.

The only exceptions to this are GRUB in Apple Macs in which GRUB in UEFI mode can boot BIOS installed OS via appleloader command (does not work in non-Apple systems), and rEFInd which technically supports booting legacy BIOS OS from UEFI systems, but does not always work in non-Apple UEFI systems as per its author Rod Smith.

However if Arch is installed in BIOS/GPT in one disk and Windows is installed in BIOS/MBR mode in another disk, then the BIOS boot loader used by Arch CAN boot the Windows in the other disk, if the boot loader itself has the ability to chainload from another disk.

Note: To dual-boot with Windows on same disk, Arch should follow the same firmware boot mode and partitioning combination used by the Windows installation.

Windows Setup creates a 100 MiB EFI system partition (except for Advanced Format 4K native drives where it creates a 300 MiB ESP), so multiple kernel usage is limited. Workarounds include:

• Mount ESP to /efi and use a boot loader that has file system drivers and is capable of launching kernels that reside on other partitions.
• Expand the EFI system partition, typically either by decreasing the Recovery partition size or moving the Windows partition (UUIDs will change).
• Backup and delete unneeded fonts in esp/EFI/Microsoft/Boot/Fonts/ [2].
• Backup and delete unneeded language directories in esp/EFI/Microsoft/Boot/ (e.g. to only keep en-US).
• Use a higher, but slower, compression for the initramfs images. E.g. COMPRESSION="xz" with COMPRESSION_OPTIONS=(-9e).

UEFI Secure Boot

All pre-installed Windows 8/8.1, 10 and 11 systems by default boot in UEFI/GPT mode and have UEFI Secure Boot enabled by default. This is mandated by Microsoft for all OEM pre-installed systems.

Arch Linux install media does not support Secure Boot yet. See Secure Boot#Booting an installation medium.

It is advisable to disable UEFI Secure Boot in the firmware setup manually before attempting to boot Arch Linux. Windows 8/8.1, 10 and 11 SHOULD continue to boot fine even if Secure boot is disabled. The only issue with regards to disabling UEFI Secure Boot support is that it requires physical access to the system to disable secure boot option in the firmware setup, as Microsoft has explicitly forbidden presence of any method to remotely or programmatically (from within OS) disable secure boot in all Windows 8/8.1 and above pre-installed systems

Fast Startup and hibernation

There are two OSs that can be hibernated, you can hibernate Windows and boot Linux (or another OS), or you can hibernate Linux and boot Windows, or hibernate both OSs.

Warning: Data loss can occur if Windows hibernates and you dual boot into another OS and make changes to files on a filesystem (such as NTFS) that can be read and written to by Windows and Linux, and that has been mounted by Windows [3]. Similarly, data loss can occur if Linux hibernates, and you dual boot into another OS etc. Windows may hibernate even when you press shutdown, see section #Windows settings.

For the same reason, if you share one EFI system partition between Windows and Linux, then the EFI system partition may be damaged if you hibernate (or shutdown with Fast Startup enabled) Windows and then start Linux, or hibernate Linux and then start Windows.

ntfs-3g added a safe-guard to prevent read-write mounting of hibernated NTFS filesystems, but the NTFS driver within the Linux kernel has no such safeguard.

Windows cannot read filesystems such as ext4 by default that are commonly used for Linux. These filesystems do not have to be considered, unless you install a Windows driver for them.

Windows settings

Fast Startup is a feature in Windows 8 and above that hibernates the computer rather than actually shutting it down to speed up boot times.

There are multiple options regarding the Windows settings for Fast Startup and hibernation that are covered in the next sections.

• disable Fast Startup and disable hibernation
• disable Fast Startup and enable hibernation
• enable Fast Startup and enable hibernation

The procedure of disabling Fast Startup is described in the tutorials for Windows 8, Windows 10 and Windows 11. In any case if you disable a setting, make sure to disable the setting and then shut down Windows, before installing Linux; note that rebooting is not sufficient.

Disable Fast Startup and disable hibernation

This is the safest option, and recommended if you are unsure about the issue, as it requires the least amount of user awareness when rebooting from one OS into the other. You may share the same EFI system partition between Windows and Linux.

Disable Fast Startup and enable hibernation

This option requires user awareness when rebooting from one OS into the other.
If you want to start Linux while Windows is hibernated, which is a common use case, then

• you must use a separate EFI system partition (ESP) for Windows and Linux, and ensure that Windows does not mount the ESP used for Linux. As there can only be one ESP per drive, the ESP used for Linux must be located on a separate drive than the ESP used for Windows. In this case Windows and Linux can still be installed on the same drive in different partitions, if you place the ESP used by linux on another drive than the Linux root partition.
• you can not read-write mount any filesystem in Linux, that is mounted by Windows while Windows is hibernated. You should be extremely careful about this, and also consider Automount behaviour.
• If you shut down Windows fully, rather than hibernating, then you can read-write mount the filesystem.

Note: You can avoid this issue for a drive by mounting a drive as an external drive in Windows and ejecting the drive in Windows before hibernating.

Enable Fast Startup and enable hibernation

The same considerations apply as in case «Disable Fast Startup and enable hibernation», but since Windows can not be shut down fully, only hibernated, you can never read-write mount any filesystem that was mounted by Windows while Windows is hibernated.

Note: Windows updates may re-enable Fast Startup, as reported in [4].

Windows filenames limitations

Windows is limited to filepaths being shorter than 260 characters.

Windows also puts certain characters off limits in filenames for reasons that run all the way back to DOS:

• < (less than)
• > (greater than)
• : (colon)
• " (double quote)
• / (forward slash)
• \ (backslash)
• | (vertical bar or pipe)
• ? (question mark)
• * (asterisk)

These are limitations of Windows and not NTFS: any other OS using the NTFS partition will be fine. Windows will fail to detect these files and running chkdsk will most likely cause them to be deleted. This can lead to potential data-loss.

NTFS-3G applies Windows restrictions to new file names through the windows_names option: ntfs-3g(8) § Windows_Filename_Compatibility (see fstab).

Installation

The recommended way to setup a Linux/Windows dual booting system is to first install Windows, only using part of the disk for its partitions. When you have finished the Windows setup, boot into the Linux install environment where you can create and resize partitions for Linux while leaving the existing Windows partitions untouched. The Windows installation will create the EFI system partition which can be used by your Linux boot loader.

Windows before Linux

BIOS systems

Using a Linux boot loader

You may use any multi-boot supporting BIOS boot loader.

Using the Windows Vista/7/8/8.1 boot loader

This section explains how to : install a linux bootloader on a partition instead of the MBR ; copy this bootloader to a partition readable by the windows bootloader ; use the windows bootloader to start said copy of the linux bootloader.

Note: Some documents state that the partition being loaded by the Windows boot loader must be a primary partition but usage of an extended partition has been documented as working.

• When installing the boot loader, install it on your /boot partition rather than the MBR. For details on doing this with GRUB, see GRUB/Tips and tricks#Install to partition or partitionless disk, for Syslinux, see the note at Syslinux#Manual install, for LILO see LILO#Install to partition or partitionless disk.

• Make a copy of the VBR:

  dd if=/dev/disk of=/path/to/linux.bin bs=512 count=1

  where /dev/disk is the path of the partition on which your bootloader is installed and /path/to/ is the mounted filesystem on which you want the copy to be readable by the Windows bootloader.

• On Windows, the linux.bin file should now be accessible. Run cmd with administrator privileges (navigate to Start > All Programs > Accessories, right-click on Command Prompt and select Run as administrator):

  bcdedit /create /d "Linux" /application BOOTSECTOR

  BCDEdit will return a UUID for this entry. This will be refered to as UUID in the remaining steps.

  bcdedit /set UUID device partition=c: (or the drive letter on which linux.bin is kept) 
  bcdedit /set UUID  path \path\to\linux.bin  
  bcdedit /displayorder UUID /addlast  
  bcdedit /timeout 30

On reboot, both Windows and Linux should now show up in the Windows bootloader.

Note: On some hardware, the Windows boot loader is used to start another OS with a second power button (e.g. Dell Precision M4500).

For more details, see https://www.iceflatline.com/2009/09/how-to-dual-boot-windows-7-and-linux-using-bcdedit/

UEFI systems

If you already have Windows installed, it will already have created some partitions on a GPT-formatted disk:

• a Windows Recovery Environment partition, generally of size 499 MiB, containing the files required to boot Windows (i.e. the equivalent of Linux’s /boot),
• an EFI system partition with a FAT32 filesystem,
• a Microsoft Reserved Partition, generally of size 128 MiB,
• a Microsoft basic data partition with a NTFS filesystem, which corresponds to C:,
• potentially system recovery and backup partitions and/or secondary data partitions (corresponding often to D: and above).

Using the Disk Management utility in Windows, check how the partitions are labelled and which type gets reported. This will help you understand which partitions are essential to Windows, and which others you might repurpose. The Windows Disk Management utility can also be used to shrink Windows (NTFS) partitions to free up disk space for additional partitions for Linux.

Warning: The first 4 partitions in the above list are essential, do not delete them.

You can then proceed with partitioning, depending on your needs. The boot loader needs to support chainloading other EFI applications to dual boot Windows and Linux. An additional EFI system partition should not be created, as it may prevent Windows from booting.

Note: It only appears when Linux is installed on the second hard disk and a new EFI system partition is created on the second hard disk.

Simply mount the existing partition.

Computers that come with newer versions of Windows often have Secure Boot enabled. You will need to take extra steps to either disable Secure Boot or to make your installation media compatible with secure boot (see above and in the linked page).

Linux before Windows

Even though the recommended way to setup a Linux/Windows dual booting system is to first install Windows, it can be done the other way around. In contrast to installing Windows before Linux, you will have to set aside a partition for Windows, say 40GB or larger, in advance. Or have some unpartitioned disk space, or create and resize partitions for Windows from within the Linux installation, before launching the Windows installation.

UEFI firmware

Windows will use the already existing EFI system partition. In contrast to what was stated earlier, it is unclear if a single partition for Windows, without the Windows Recovery Environment and without Microsoft Reserved Partition, will not do.

Follows an outline, assuming Secure Boot is disabled in the firmware.

1. Boot into windows installation. Watch to let it use only the intended partition, but otherwise let it do its work as if there is no Linux installation.
2. Follow the #Fast Startup and hibernation section.
3. Fix the ability to load Linux at start up, perhaps by following #Cannot boot Linux after installing Windows. It was already mentioned in #UEFI systems that some Linux boot managers will autodetect Windows Boot Manager. Even though newer Windows installations have an advanced restart option, from which you can boot into Linux, it is advised to have other means to boot into Linux, such as an arch installation media or a live CD.

Windows 10 with GRUB

The following assumes GRUB is used as a boot loader (although the process is likely similar for other boot loaders) and that Windows 10 will be installed on a GPT block device with an existing EFI system partition (see the «System partition» section in the Microsoft documentation for more information).

Create with program gdisk on the block device the following three new partitions. See [5] for more precise partition sizes.

Min size	Code	Name	File system
16 MB	0C01	Microsoft reserved	N/A
~40 GB	0700	Microsoft basic data	NTFS
300 MB	2700	Windows RE	NTFS

Create NTFS file systems on the new Microsoft basic data and Windows RE (recovery) partitions using the mkntfs program from package ntfs-3g.

Reboot the system into a Windows 10 installation media. When prompted to install select the custom install option and install Windows on the Microsoft basic data partition created earlier. This should also install Microsoft EFI files in the EFI system partition.

After installation (set up of and logging into Windows not required), reboot into Linux and generate a GRUB configuration for the Windows boot manager to be available in the GRUB menu on next boot.

Troubleshooting

Couldn’t create a new partition or locate an existing one

See #Windows UEFI vs BIOS limitations.

Cannot boot Linux after installing Windows

See Unified Extensible Firmware Interface#Windows changes boot order.

Restoring a Windows boot record

By convention (and for ease of installation), Windows is usually installed on the first partition and installs its partition table and reference to its bootloader to the first sector of that partition. If you accidentally install a bootloader like GRUB to the Windows partition or damage the boot record in some other way, you will need to use a utility to repair it. Microsoft includes a boot sector fix utility FIXBOOT and an MBR fix utility called FIXMBR on their recovery discs, or sometimes on their install discs. Using this method, you can fix the reference on the boot sector of the first partition to the bootloader file and fix the reference on the MBR to the first partition, respectively. After doing this you will have to reinstall GRUB to the MBR as was originally intended (that is, the GRUB bootloader can be assigned to chainload the Windows bootloader).

If you wish to revert back to using Windows, you can use the FIXBOOT command which chains from the MBR to the boot sector of the first partition to restore normal, automatic loading of the Windows operating system.

Of note, there is a Linux utility called ms-sys (package ms-sys^AUR in AUR) that can install MBR’s. However, this utility is only currently capable of writing new MBRs (all OS’s and file systems supported) and boot sectors (a.k.a. boot record; equivalent to using FIXBOOT) for FAT file systems. Most LiveCDs do not have this utility by default, so it will need to be installed first, or you can look at a rescue CD that does have it, such as Parted Magic.

First, write the partition info (table) again by:

# ms-sys --partition /dev/sda1

Next, write a Windows 2000/XP/2003 MBR:

# ms-sys --mbr /dev/sda  # Read options for different versions

Then, write the new boot sector (boot record):

# ms-sys -(1-6)          # Read options to discover the correct FAT record type

ms-sys can also write Windows 98, ME, Vista, and 7 MBRs as well, see ms-sys -h.

Restoring an accidentally deleted EFI system partition

If you have a GPT-partitioned disk and erased (e.g. with mkfs.fat -F32 /dev/sdx) the EFI system partition, you will notice that Windows Boot Manager will either disappear from your boot options, or selecting it will send you back to the UEFI.

To remedy it, boot with a Windows installation media, press Shift+F10 to open the console (or click NEXT > Repair Computer > Troubleshoot… > Advanced > Command Prompt), then start the diskpart utility:

X:\Sources> diskpart
DISKPART> list disk

Select the appropriate hard drive by typing:

DISKPART> select disk number

Make sure that there is a partition of type system (the EFI system partition):

DISKPART> list partition

Select this partition:

DISKPART> select partition number

and assign a temporary drive letter to it:

DISKPART> assign letter=G:

DiskPart successfully assigned the drive letter or mount point.

To make sure that drive letter is correctly assigned:

DISKPART> list vol

 Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
 ----------  ---  -----------  -----  ----------  -------  ---------  --------
 Volume 0     E                       DVD-ROM         0 B  No Media
 Volume 1     C                NTFS   Partition    195 GB  Healthy    Boot
 Volume 2         WINRE        NTFS   Partition    400 MB  Healthy    Hidden
 Volume 3     G                FAT32  Partition    499 MB  Healthy    System

Close diskpart:

DISKPART> exit

Navigate to C:\ (or what your system drive letter is):

X:\Sources> cd /d C:\

Next is the «magic» command, which recreate the BCD store (with /s for the mount point, /f for firmware type, optionally add /v for verbose):

C:\> bcdboot C:\Windows /s G: /f UEFI

Tip: If it hangs up after a minute, hit Ctrl+c. This happens sometimes, but you will get a message like boot files successfully created and it will have worked just fine.

You should now have Windows Boot Manager working as a boot option, and thus have access to Windows. Just make sure to never format your EFI system partition again!

Note: Remove the drive letter G assigned to the EFI system partition to keep it from showing up in My Computer.

See [6], [7] and [8].

The EFI system partition created by Windows Setup is too small

By default, Windows Setup creates a 100 MiB EFI system partition (except for Advanced Format 4K native drives where it creates a 300 MiB ESP). This is generally too small to fit everything you need. You can try different tools to resize this partition, but there are usually other partitions in the way, making it, at the very least, difficult.

If you are installing Windows from scratch, you can dictate the size of the EFI system partition during installation[9]:

1. Select your installation target and make sure it has no partitions.
2. Click New and then the Apply buttons. The Windows installer will then generate the expected partitions (allocating nearly everything to its primary partition) and just 100MB to the EFI.
3. Use the UI to delete the System, MSR, and Primary partitions. Leave the Recovery partition (if present) alone.
4. Press Shift+F10 to open the Command Prompt.
5. Type diskpart.exe and press Enter to open the disk partitioning tool.
6. Type list disk and press Enter to list your disks. Find the one you intend to modify and note its disk number.
7. Type select disk disk_number with the disk number to modify.
8. Type create partition efi size=size with the desired size of the ESP in Mebibytes (MiB), and press Enter. See the note at EFI system partition#Create the partition for the recommended sizes.
9. Type format quick fs=fat32 label=System and press Enter to format the ESP
10. Type exit and press Enter to exit the disk partitioning tool and exit followed by Enter again.

Once Windows is installed, you can resize the primary partition down within Windows and then reboot and go about your usual Arch install, filling the space you just created.

Alternatively, you can use the Arch install media to create a single EFI system partition of your preferred size before you install Windows on the drive. Windows Setup will use the EFI system partition you made instead of creating its own.

Unable to install Windows Cumulative Update on BIOS system

On BIOS systems, Windows cumulative updates may fail with the error We couldn’t complete the updates. Undoing changes. Don’t turn off your computer. In such case, while in Windows, you need to set the Windows partition as active.

C:\> diskpart
DISKPART> list disk
DISKPART> select disk number
DISKPART> list partition
DISKPART> select partition number
DISKPART> active
DISKPART> exit

After successfully installing the Windows update, mark back your Linux partition as active, using commands above.

Time standard

• Recommended: Set both Arch Linux and Windows to use UTC, following System time#UTC in Microsoft Windows. Some versions of Windows revert the hardware clock back to localtime if they are set to synchronize the time online. This issue appears to be fixed in Windows 10.
• Not recommended: Set Arch Linux to localtime and disable all time synchronization daemons. This will let Windows take care of hardware clock corrections and you will need to remember to boot into Windows at least two times a year (in Spring and Autumn) when DST kicks in. So please do not ask on the forums why the clock is one hour behind or ahead if you usually go for days or weeks without booting into Windows.

Bluetooth pairing

When it comes to pairing Bluetooth devices with both the Linux and Windows installation, both systems have the same MAC address, but will use different link keys generated during the pairing process. This results in the device being unable to connect to one installation, after it has been paired with the other. To allow a device to connect to either installation without re-pairing, follow Bluetooth#Dual boot pairing.

See also

• Booting Windows from a desktop shortcut
• One-time boot into Windows partition from desktop shortcut
• Windows 7/8/8.1/10 ISO to Flash Drive burning utility for Linux (MBR/GPT, BIOS/UEFI, FAT32/NTFS)

В этой статье разберём разные варианты установки двух систем на один компьютер используя загрузчик GRUB 2, это называется Dual boot.

Что такое dual boot или multi boot

Multi boot (множественная загрузка) — это когда вы можете на одном компьютере на свой выбор загружать разные операционные системы. Чаще всего это Windows и различные Linux системы. На одном компьютере можно разместить две и более операционных систем.

Dual boot (двойная загрузка) — это вариант Multi boot, если используется всего 2 системы.

Зачем вообще держать на своём компьютере несколько систем? Давайте я приведу несколько примеров использования dual boot.

Если у вас установлена Windows, но вы хотите попробовать какой-нибудь Linux. Для этого вы рядом со своей Windows устанавливаете Linux и загружаетесь в Linux. Если вы что-то случайно поломаете в Linux, то вы всегда сможете загрузиться в привычную Windows. Или если вам нужно срочно выполнить какую-нибудь работу и вы знаете как это делается на Windows, то и в этом случае вы можете загрузить Windows.

Еще вам может понадобиться Dual boot, если вам удобно работать на Linux. А Windows вы используете только для игр. Ну или одними программами вы пользуетесь на Linux, а другими на Windows. В обоих случаях вы можете загружать иногда Linux, а иногда Windows.

Ну и третий вариант. У вас дома один компьютер. Вы предпочитаете работать в Linux, а другие члены вашей семьи используют Windows.

Минусы двойной загрузки

Каждая система будет занимать место на жёстком диске. И если Linux обычно занимает не так много (8 — 16 GB), то Windows будет занимать 50-60 GB.

Из Linux системы вы можете получить доступ ко всем файлам в Windows. Вы даже можете случайно повредить Windows, так как у вас будет доступ ко всем её файлам. А вот из WIndows получить доступ к файлам Linux нельзя, более того Windows будет предлагать отформатировать разделы на которых расположена Linux. Главное не забыть для чего эти разделы и не согласиться с форматированием.

Ну и конечно две системы усложняют весь процесс настройки.

Принципы работы

Причины использовать Dual boot могут быть разные. Но нужно знать некоторые базовые вещи для использования такой загрузки.

• Каждая система устанавливается либо на разные разделы одного диска, либо на разные диски.
• Компьютер может работать под управлением BIOS и искать загрузчик на загрузочном диске в MBR. А может работать под управлением UEFI и искать ESP или EFI раздел для запуска загрузчика от туда.
• Различные операционные системы используют различные установщики.
  • Например Windows при установки затрет GRUB 2 своим загрузчиком, который не умеет загружать Linux системы. Тогда нужно будет восстанавливать GRUB 2. Кстати GRUB 2 умеет загружать и Linux и Windows.
  • Ubuntu также устанавливает свой GRUB 2 не спрашивая и затирает установленный ранее загрузчик от другой системы.
  • А вот Debian при установки спрашивает, нужно ли устанавливать GRUB 2 или нет. И если у вас уже используется другой загрузчик, от другой системы, то вы можете и отказаться от установки GRUB 2.
• При двойной загрузки вам понадобится специальный загрузчик, который может запускать различные системы на выбор. Например уже изученный нами GRUB 2. Есть и другие загрузчики, но в этом курсе они не рассматриваются.

Я понимаю что самый распространённый вариант использования Dual Boot это Windows + Linux. Но так как у нас курс по администрированию LInux (Ubuntu и Debian). То в следующих статьях я покажу как установить Ubuntu 22.04 рядом с Debian 11. А установку Ubuntu рядом с Windows тоже планирую описать, но в отдельной статье.

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You will learn everything you need to know about dual-booting Linux and Windows.

I assume you already have Windows installed on your computer and you only need to install Linux to dual boot. This post will guide you through the following key points of the dual boot installation:

• Essential BIOS settings for successful dual boot.
• How to shrink your Windows partition to get free space for Linux.
• How to install Linux, using Linux Mint as an example.
• How to set the boot order in your computer to see the menu where you can choose between Linux and Windows to boot.
• Finally, I will explain why I am not a fan of dual-booting and why I recommend using Windows in a virtual machine as I showed in this post.

*NOTE: Before you apply any actions from in this post, please back up all your important data.*

BIOS settings

Unfortunately, most of the computers have BIOS configured specifically for Windows, and likely you won’t be able to install Linux on it without changing some settings. BIOS interface may differ from one computer to another but the main settings are the same.

I will use the BIOS of my Acer Swift 1 laptop as an example here.

Get into BIOS

First, you need to get into BIOS, usually, you just need to press a specific key during the boot. In my Acer Swift 1, I press F2. Just google your computer model and bios key term, and you will find the key you need to press. Sometimes, you may also see it on the screen during the boot:

Set the BIOS password

Next, you may need to set a password in your BIOS because it won’t allow you to change any security settings without a password. This is the menu to set the password on my Acer Swift 1:

You should be able to find the same in your BIOS. It is also possible that you can proceed without setting a password.

Disable Secure booting and change the Boot order

Next, you need to go to the Boot menu and disable Secure booting and move your bootable USB flash drive to the first place in the boot order:

Check this description of the commands on the right or bottom of your BIOS interface, it explains how to navigate and change options in your BIOS.

I am not going to stop here on how to create a bootable USB drive. I have already explained how to create a bootable USB from the command line or using graphical programs.

Save BIOS settings

In the end, go to the exit menu and exit BIOS with saving the changes:

If you have done everything correctly, you should boot in your Live USB Linux system:

Get free space for Linux

Boot into Live Linux session

Boot from the Live Linux USB. I will use Linux Mint installer as an example here, if you use Ubuntu or any Ubuntu-based distro, the process will not differ at all. If your distro is not Ubuntu-based, you still need to do the same steps as you will see in this post but the installer may look slightly different.

To install Linux alongside Windows, you can actually select such an option in the installation wizard:

It will automatically find free space on your hard drive and install Linux there. However, if you want to have little more control over how much space you allocate to Windows and Linux, you can get free space and assign it for Linux manually.

Shrink the Windows partition with GParted

Most of the Linux distros have GParted included in a Live ISO. If it is not, install it from the Software Center. Then open GParted and select the hard drive with your Windows installed:

Your Windows hard drive will be partitioned similarly to the one you see above. Most likely it will have the EFI partition, and this means you need to install Linux in the EFI mode too.

To shrink the Windows partition to get free space for Linux, you need to select the largest partition, click on the Partition menu in GParted, and select resize.

All white space is free space. So, you can shrink this partition with your mouse, or by selecting its size precisely with the number. You can take a maximum of free space for Linux if you aim to use mainly Linux, but leave some free space for Windows too, because it may not be able to work without free space left.

Click resize. Read this warning to know the risk and click OK. You will see how your partitions will look like after you apply the resizing:

So far, no changes to your hard drive have been applied. It is only a plan of action. You still can cancel everything, if you have done a mistake somewhere. However, if you are happy with this partition table. Click apply. This action will be irreversible.

Resizing will take some time. Hopefully, it will finish successfully and you can proceed with the installation.

Install Linux

To install Linux, click on the Install icons on your desktop or in your menu.
The installation process is pretty standard.

I recommend to include the third party software in the installation:

Select Manual partitioning

As I mentioned before, you can select the option to Install Linux alongside Windows automatically, but I personally prefer the manual way. That’s why we shrank the Windows partition and released some free space for Linux. Manual way not only gives more control but it also helps to understand what happens to your system when you install two systems alongside each other. So, select Something else here:

Create Linux Partition

The new screen will show you the partitions of your hard drive. You need to select the free space we have created in the previous step. Then click on the add sign, to create a Linux partition in this free space:

You can keep all the options at default here but importantly you need to assign / as a mounting point to this partition.

You can also split this free space into two parts and assign one to the system / and one to /swap. But I believe it is much better to use a swap file instead. Ubuntu installer creates a swap file by default.
I already explained the difference between a swap file and swap partition previously.

Check the EFI partition

Next, you need to select the EFI partition, it is usually of several hundred megabytes in size. Make sure it is detected as EFI:

Boot loader installation

Boot loader installation doesn’t matter here because it will be UEFI installation, so the boot loader will be installed in the EFI partition. You can keep the default selection.

Format column

Finally, check that only the new Linux partition will be formatted in the Format column. Because if you have other partitions selected for formatting, be careful you will lose all the data stored in those partitions. If everything is fine, click Install.

Finalize the installation

While the system is installing, select your location, provide your user information, set the password, etc.:

And then just wait until the system is installed.

After the installation, reboot the system and do not forget to remove your installation USB when you are requested to do so:

Boot into the new system

You should see this GRUB menu after the reboot. Here you can select between Linux, which will boot by default in 10 sec, and Windows:

Boot options in BIOS

If it happened that after the reboot, you booted directly in your Windows and you did not see any Linux menu, do not get upset. Likely, you have done everything right and you just need to change the boot order in your BIOS. Like I had to do in my Acer Swift 1.

In the Main tab, find the Boot menu and enable it:

Change the Boot order

Then go to the Boot order and you should see an additional boot option there that appeared after you installed Linux. In my case, it is still called Windows Boot Manager without the code in brackets. This is actually my Linux boot file. I do not know why BIOS branded it as Windows. So, I make it a first boot option:

And save the BIOS changes. After the reboot, you should see the GRUB menu with the choice of boot options.

If you still boot into Windows by default, try to open the boot menu during the start of your system by pressing the F12 key (or whatever key is assigned to your BIOS Boot menu). It should bring this BIOS boot menu:

Where I can choose Ubuntu and my Linux Mint will boot. So, the BIOS Boot menu helps to make sure that Linux works, you just need to check your boot order settings, maybe Linux is not the first option there. Try different orders until you get Linux booting the first.

Why I do not recommend dual-booting

There are three main reasons I stopped dual-booting and this is also why I do not recommend dual boot.

1. If you use Windows in dual boot, it is possible that some updates of Windows may break your Linux installation. Theoretically, it should not happen, but it happens. Maybe Windows changes the Linux bootloader in the UEFI partition. I do not know.

2. If you dual boot, you will never switch to Linux. If you are used to Windows, you will tend to boot into Windows more often and you won’t like to reboot to get to Linux. So, you will not use Linux much and thus will never switch to Linux completely.

3. On the other hand, if you prefer Linux, Windows will just take too much space on your hard drive that is never used. So, this is not good either.

I recommend using Windows in a Virtual machine such as VirtualBox. This way your Windows can be accessed from within Linux. Windows will be less powerful than if it was installed in dual boot, but you still can do most of the things you would normally do. A virtual machine also isolates your Windows file system and this provides better protection against viruses. You can read my post on how to install Windows 10 in VirtualBox and maybe you will like that option more than dual-booting.