2

Before I had:

  • Partition 1: 100MB (EFI)

  • Partition 2: 300GB Windows 7

Now I added these 2 partitions and installed Ubuntu 18.04:

Then I read a few things and realized:

  1. It's a bad idea to have 2 EFI partitions on the same disk. Is this correct indeed? Or is it the normal practice to have 2 EFI partitions for a Windows-Linux dual boot? Which solution is the best?

  2. Therefore I deleted "Partition 3". Of course I cannot boot on Ubuntu anymore, but I can boot on the Ubuntu Live USB. Now that I only have Partition 1, 2, 4, how to to recreate a boot loader for Ubuntu?

Basj
  • 133

1 Answers1

3

You could have copied the /EFI/Boot & /EFI/ubuntu folders from the second ESP to the first. And then used efibootmgr to update actual entry in UEFI to use correct ESP.

You can only have one working ESP per device. Boot flag is used by parted/gparted to define the ESP using a long GUID that the UEFI uses to find the ESP.

Easiest now just to reinstall grub2. And Boot-Repair makes that easy. If you have issues, post the link, otherwise I expect the auto fix will work, but be sure to boot Ubuntu live installer in UEFI mode & add Boot-Repair to it.

Please copy & paste the pastebin link to the Boot-info summary report ( do not post report), do not run the auto fix till reviewed.

https://help.ubuntu.com/community/Boot-Repair

https://help.ubuntu.com/community/Grub2/Installing#UEFI

oldfred
  • 12,100
  • Thanks! With the first option (if I had copied the content of second ESP to first), which efibootmgr command would be required, with which parameters? (Could you include it?) – Basj Jun 27 '20 at 07:33
  • There is also a third option : reinstall Ubuntu from scratch, it's probably the easiest (just 15 minutes). Then should I choose /dev/sda or /dev/sda1 (=windows efi partition) as "Device for boot loader installation"? – Basj Jun 27 '20 at 07:35
  • See also man efibootmgr Some examples here: https://askubuntu.com/questions/486752/dual-boot-win-8-ubuntu-loads-only-win & https://askubuntu.com/questions/668506/changed-the-uefi-motherboard-on-a-dell-laptop-now-it-says-no-os-detected It defaults to first drive, so if ESP not sda1, you have to add parameters for drive & partition. – oldfred Jun 27 '20 at 13:16
  • Thank you. About your second sentence, what exactly defaults to first drive? – Basj Jun 27 '20 at 13:20
  • See man efibootmgr. If you do not use the -d and -p parameters it defaults to sda1. You have to specify drive with -d and partition with -p. See the various examples, but be sure which is your ESP - efi system partition. – oldfred Jun 27 '20 at 17:53