GRUB issue

[cookiemuncher]

The solution seems to be to use a separate boot partition to the one used by Windows.

[Qqmike]

The solution seems to be to use a separate boot partition to the one used by Windows.

I think you mean 'separate ESP partition.'
It sounds like you are on top of things and have a good skill level.

FWIW, I just did a how-to on using two ESPs, it is NOT for Windows, but it should still apply here,

Dual booting two (or more) *ubuntu operating systems in UEFI mode -- 1 drive or 2 drives, 1 ESP or 2 ESPs
https://www.kubuntuforums.net/forum/...-esp-or-2-esps

[cookiemuncher]

I think you mean 'separate ESP partition.'
It sounds like you are on top of things and have a good skill level.

FWIW, I just did a how-to on using two ESPs, it is NOT for Windows, but it should still apply here,

Dual booting two (or more) *ubuntu operating systems in UEFI mode -- 1 drive or 2 drives, 1 ESP or 2 ESPs
https://www.kubuntuforums.net/forum/...-esp-or-2-esps

Great writeup Qqmike

My setup now:

$ lsblk -p -o NAME,FSTYPE,SIZE,MOUNTPOINTS
NAME FSTYPE SIZE MOUNTPOINTS
/dev/sda 465.8G
├─/dev/sda1 ntfs 549M
├─/dev/sda2 16M
├─/dev/sda3 ntfs 456.9G
├─/dev/sda4 ntfs 673M
└─/dev/sda6 vfat 1.5G
/dev/sdb 232.9G
├─/dev/sdb1 ntfs 156G
├─/dev/sdb2 swap 5G
├─/dev/sdb3 ext4 70.8G /
└─/dev/sdb4 vfat 1G /boot/efi
/dev/nvme0n1 465.8G
└─/dev/nvme0n1p1 ext4 465.8G /srv/nvme

sda6 is my ESP for booting Windows and sdb4 for booting Linux.

[Qqmike]

Sounds like you got it working.
Two ESPs, each on a separate disk for a separate OS.
(I see, too, that you have three disks.)

Hope all is good now!

[cookiemuncher]

Sounds like you got it working.
Two ESPs, each on a separate disk for a separate OS.
(I see, too, that you have three disks.)

Hope all is good now!

All good thanks.

Route I took:
1. Created new partition on the Linux drive using Gparted on a live Linux USB
2. Set this partition as ESP and bootable using Gparted
3. Reboot into 25.04
4. Unmount /dev/sda6 (Windows ESP, currently shared with Linux)
5. Edited /etc/fstab to link to the correct (new) ESP (edit the UUID)
6. Mounted new ESP (sudo mount -a)
7. sudo grub-install /dev/sdb4
8. sudo update-grub
9. rebooted

I hope I haven't missed any steps.


BUT, would it not be a good thing that during the install process and a Windows installation is detected that some advice be given regarding creating a separate ESP for the Linux install, and not automatically use the current Windows ESP?

[kc1di]

I haven't run a machine with window or dual boot in a long time, but as I remember windows always wanted to be in control and sounds like that has not changed.
But glad you got it sorted and hope it will help others. I was following this thread simply because on my machine when I tried to install 25.04 in legacy bios mode (no UEFI) if simply would not not matter how I tried install grub correctly. So ended up installing in UEFI and it all worked great.

[Qqmike]

BUT, would it not be a good thing that during the install process and a Windows installation is detected that some advice be given regarding creating a separate ESP for the Linux install, and not automatically use the current Windows ESP?

Good question! Who knows?!
It certainly seems your approach (two ESPs) works fine.
But is it always necessary? That's the question.
It seems that Windows always throws some curve ball at the game.
And Windows 12 might have its own curve balls we didn't see coming.
If I used Windows in dual boot, for sure I would use two ESPs. No question. Even if I only used one disk, I'd use two ESPs.

[Qqmike]

Post 20:

4. Unmounted /dev/sda6 (Windows ESP)

Yes. So that the Windows ESP is not visible (to any utility or installer).
(You can also just turn off the boot flag to that ESP (using gparted), and then later turn it back on.)