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Re: problems dual booting Ubuntu 16.04 and Windows 10
From: |
Pascal Hambourg |
Subject: |
Re: problems dual booting Ubuntu 16.04 and Windows 10 |
Date: |
Fri, 11 May 2018 21:05:29 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux i686; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 |
Le 11/05/2018 à 18:05, David Collier a écrit :
Disk /dev/sdc: 465.8 GiB, 500107862016 bytes, 976773168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: AF6118F0-6BF8-460C-9622-F5BDA7EE3204
Device Start End Sectors Size Type
/dev/sdc1 2048 1023999 1021952 499M Windows recovery environment
/dev/sdc2 1024000 1226751 202752 99M Microsoft basic data
/dev/sdc3 1226752 1259519 32768 16M Microsoft reserved
/dev/sdc4 1259520 976773119 975513600 465.2G Microsoft basic data
(...)
/dev/sdc2: SEC_TYPE="msdos" UUID="A879-04E5" TYPE="vfat" PARTLABEL="EFI
system partition" PARTUUID="2987d536-85c4-4a68-ad8a-7c880054bda9"
At first I was surprised not to see an EFI system partition on sdc, but
here it is, sdc2. It just has the wrong partition type identifier in the
partition table, which should be "EFI system partition" instead of
"Microsoft basic data". You should correct this with your favourite
GPT-capable partition editor (gparted, parted, fdisk, gdisk...)
This means that the system did not boot in EFI mode. It explains why
os-prober cannot detect Windows EFI boot loader.
Check what's in /boot and /boot/grub : I guess there is no /boot/efi
directory nor /boot/grub/x86_64-efi, but there is a /boot/grub/i386-pc
directory.
yes, these guesses are correct. So, is there a way to make grub include
windows 10 option in this case? How come the BIOS/UEFI, (whatever my PC's
firmware is that is :) can boot both, but grub can not?
Windows was installed for EFI boot, and I do not know any way around
this except by reinstalling it for BIOS/legacy booting. So you have to
install the GRUB boot loader for EFI booting (GRUB EFI). The GRUB
distribution is split in multiple packages for all supported targets and
usually you need to install the package grub-efi-amd64, but since you
built GRUB from source, I'll assume the needed files are already present.
First, you must mount the EFI partition sdc2 on /boot/efi (create the
directory if it does not exist, and make the mount persistent in fstab -
as usual, use the UUID, not the unreliable device name).
Then ideally you must find a way to boot in EFI mode and start a shell
in Ubuntu. For example boot from an EFI-capable live system or whatever,
chroot into Ubuntu's root and mount everything required (/dev, /proc,
/sys, /boot/efi...). efibootmgr should not complain about EFI variables
not being supported.
From there, install GRUB EFI :
grub-install --target=x86_64-efi --bootloader-id=Ubuntu
This will install GRUB EFI as /boot/efi/EFI/Ubuntu/grubx64.efi and will
try to register a boot entry for it in the UEFI firmware NVRAM. If it
succeeds, efibootmgr should show a new "Ubuntu" entry, and it should
also be present in the UEFI boot menu. While in EFI mode, os-prober
should detect Windows Boot Manager and you can run update-grub to
include Windows in GRUB's menu.
If you cannot run Ubuntu in EFI mode, here are a few workarounds :
a) Some UEFI firmware allow to create a custom boot using a given EFI
boot file. Select \EFI\Ubuntu\grubx64.efi on the drive corresponding to sdc.
b) Install GRUB EFI as the fallback boot loader with
grub-install --target=x86_64-efi --removable
and, in the UEFI boot menu, choose to boot from the drive corresponding
to sdc in EFI mode (may be referred to as "EFI shell")
c) Rename the Windows boot loader /boot/efi/EFI/Microsoft/bootmgfw.efi
and replace it with a copy of grubx64.efi. Yes, that's ugly but is
sometimes the only way to boot in EFI mode the first time. After
reinstalling GRUB EFI without error, restore the original bootmgfw.efi
so that you can boot Windows again.
- problems dual booting Ubuntu 16.04 and Windows 10, David Collier, 2018/05/08
- Re: problems dual booting Ubuntu 16.04 and Windows 10, David Collier, 2018/05/10
- Re: problems dual booting Ubuntu 16.04 and Windows 10, Pascal Hambourg, 2018/05/11
- Re: problems dual booting Ubuntu 16.04 and Windows 10, David Collier, 2018/05/12
- Re: problems dual booting Ubuntu 16.04 and Windows 10, Pascal Hambourg, 2018/05/12
- Re: problems dual booting Ubuntu 16.04 and Windows 10, David Collier, 2018/05/12
- Re: problems dual booting Ubuntu 16.04 and Windows 10, Pascal Hambourg, 2018/05/13
- Re: problems dual booting Ubuntu 16.04 and Windows 10, David Collier, 2018/05/13
- Re: problems dual booting Ubuntu 16.04 and Windows 10, Pascal Hambourg, 2018/05/14
- Re: problems dual booting Ubuntu 16.04 and Windows 10, David Collier, 2018/05/15
- Re: problems dual booting Ubuntu 16.04 and Windows 10, Pascal Hambourg, 2018/05/15