Re: problems dual booting Ubuntu 16.04 and Windows 10

[David Collier]

On Fri, May 11, 2018 at 12:05 PM Pascal Hambourg <address@hidden>
wrote:

> Le 11/05/2018 à 18:05, David Collier a écrit :
> [..]

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...)


I did that.


> [..]

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.


Did all this after booting Ubuntu from a USB stick. Somehow first time
around efibootmgr inside chroot still complained about variables not being
avaialbe, even though the bios screen was showing USB stick as being UEFI
AND efibootmgr outside chroot was working fine.

I decided to try again because the original boot was not clean, and this
time it worked, efibootmgr inside chroot now shows Windows Boot Manager and
Patriot Memory PMAP (does not show the main Ubuntu still, must be because
it boots in a different mode, as you mentioned).


>  From there, install GRUB EFI :
>
> grub-install --target=x86_64-efi --bootloader-id=Ubuntu
>
>
this is where it fails, it complaints that
/usr/local/lib/grub/x86_64_efi/modinfo.sh does not exist. And indeed it
does not, it looks like I have /usr/local/lib/grub/i386-pc, but if I use
i386-pc in the command line it prints

grub-install: error: install device isn't specified

is something missing from the command line? I did not want to experiment
any more, as I don't want to break existing Linux boot :)

thank you,
-dc