My desktop has a NVMe drive and a HDD. I installed Win10 on the NVMe and tried installing Ubuntu 18.04 on the HDD. In the Ubuntu installer I could see Win10 installed on NVMe as /sda, so I installed Ubuntu on the HDD listed as /sdb.

I created the partitions on /sdb as follows: 1) efi 2) boot 3) root 4) home

I was hoping that all of the Ubuntu files including the efi would be created on /sdb. However, when I restarted the computer as the Ubuntu install finished, I could see the efi installed on the NVMe rather than the HDD. Was this meant to happen? My concern is that if I decide to remove the NVMe at some point, I won't be able to boot into the Ubuntu sitting on the HDD.

Could you please shed some light on this? Am I talking nonsense here?

Many thanks!

  • 1
    You only need one EFI partition. In my system, windows is installed on sda and so is the EFI partition. My Ubuntu installation is on sdb. Both OSs use the same EFI partition. And yes, if you remove the drive with the EFI partition on it, that will cause problems. – Organic Marble Aug 11 '18 at 0:08

Run the installer again. The reason it's on the NVMe is because that was probably the drive highlighted in the installer. When you reach the "Install on _______ drive" screen, click the dropdown window and select /sdb.


  • With Ubuntu's version of grub in UEFI installs, the combo box does not work. Grub always installs to first drive. I do suggest partitioning in advance and copying the folders on the ESP on the first drive to the second drive, but that really is just a backup. – oldfred Aug 11 '18 at 3:38
  • I think that is what has happened @oldfred. I did change the drive in the dropdown on the installer. Is there a way around this? Shall I physically remove the NVMe before the installation? Not ideal but... – sr-js Aug 11 '18 at 4:54
  • @oldfred shouldn't it be possible to unmount the ESP, mount the other ESP and then simply run sudo grub-install. Of course, /etc/fstab has to be edited as well. If we want to control the boot-loader location during installation of the OS, the Something else-option should be sufficient, we just need to define which partition to use for the ESP while we are in the partitioning step. – mook765 Aug 11 '18 at 5:53
  • There is a newer grub in 18.10 and during install I told it not to use sda's ESP, but use ESP on sdb. It still overwrote the ESP on sda. Specific install instructions with efibootmgr will install to another drive and Boot-Repair then can also do it, but Ubuntu installer does not. Several bug reports (for years) are there on this issue. – oldfred Aug 11 '18 at 12:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.