Re: problems dual booting Ubuntu 16.04 and Windows 10

[David Collier]

Guys, thank you for your replies which I missed because I did not subscribe
to the list before sending the first message. Turns out the replies are not
sent to the topic openers, I have subscribed now.

Not sure if this message will me attached to the original thread or not,
quoting here by hand:
==================================================
Pascal Hambourg's reply:

> Le 08/05/2018 à 06:58, David Collier a écrit :
>
>> I am having problems trying to make grub boot Windows 10. (I tried both
>> version which came with 16.04 and the latest and greatest)
>
> Version of what ?
> What versions ?
> The latest and greatest what ?
>

I am talking about grub versions. I first tried enabling dual boot using
grub version which was available through 'apt-get install grub' on Ubuntu
16.04, then I cloned git://git.savannah.gnu.org/grub.git and
built/installed grub myself.

>>  what happens,
>> it does not recognize any partitions of the hard drive where Windows 10
is
>> installed.
>
> How do you know ? What do you do and what happens exactly ?
>

what happens is that when I run grub-mkconfit/update-grub the entry for
Windows 10 does not get added to the grub boot menu.

When I switch into grub command mode during boot, the 'ls' command shows
the disks installed on the computer, but does not show any partitions on
the disk where windows 10 is.

> Did you install Ubuntu and Windows in the same boot mode (EFI or BIOS) ?
>

Yes, both installed using UEFI, on a computer which already had Ubnuntu I
added a hard drive and installed Windows 10 on it.

>> I can boot Windows by changing the BIOS default boot flow, the UEFI BIOS
is
>> able to do it just fine, but grub just does not refuse to detect Windows
>> boot partition, or any partition on that drive to that matter. I used the
>
> "does not refuse" = "accepts" ?
>
my mistake, I meant to say "but grub just refuses to detect"

>> 'disks' utility to change format of the Windows boot partition from FAT
to
>> NTFS, converting it to NTFS makes the BIOS stop recognizing it, but still
>> does not help grub to recognize it.
> Do you mean the EFI partition ? The BIOS does not care about Windows boot
partition.

I guess this is a terminology discrepancy, I am used to 'UEFI BIOS' and
'Legacy BIOS', if we are to follow your convention, my computer boots using
UEFI.

>
> Please post the output of the following commands :
>
> dpkg -l "grub*"

I built grub from source and instaledl it, what I have now is

$ grub-mkconfig --version
grub-mkconfig (GRUB) 2.03


> fdisk -l

$ sudo fdisk -l /dev/sdc
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

> blkid

$ for d in /dev/sdc*; do blkid $d; done
/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

> os-prober

$ sudo os-prober
/dev/sde1:unknown Linux distribution:Linux:linux


> efibootmgr -v

$ efibootmgr -v
efibootmgr: EFI variables are not supported on this system.

>
> Don't worry if the last one gives an error.

thank you,
-dc