Grub not showing after windows first boot

cn flag

I have made a dual boot installation of ubuntu 20.04.1 server after resizing the windows partitions on the only available disk.

I followed the installation procedure and after a successful installation it asked me to remove the installation media and reboot, which I did. After rebooting GRUB was shown and both boot option appeared (ubuntu and windows boot manager). While I keep on selecting ubuntu as the boot option, GRUB keeps appearing but after selecting windows for the first time, GRUB is no longer shown.

Any ideas what could be the issue?

ChanganAuto avatar
us flag
Sometimes Windows updates, when reboots are needed, change the boot order for your convenience. Check UEFI > Boot.
Paul Benson avatar
us flag
Need to see your partitions first - `sudo parted -l`, and make and model of computer. Also in Windows if you run command `bcdedit` (need to run this with administrator privilege), what is shown as 'Path' in Windows Boot Manager? Are you using Secure Boot?
oldfred avatar
cn flag
What brand/model system? Both installs are UEFI?
cn flag
I have a damaged Surface 3 Pro. the output of bcdedit is on and the disk manager output is from what I was able to see by running `efibootmgr` with the ubuntu live usb is that the boot order has the windows boot manager before the ubuntu one. I tried to set the order using that tool but it did not work.
cn flag

Thank you all for the suggestions. The solution ended up coming as a combination of various searches I made that had overlapping similarities. Below are the steps description of what in the end allowed me to resolve the issue.

First I needed to confirm that GRUB was still present. I did that by following this post answer in order to access the content of the EFI partition while in Windows. As explained in the post, I mounted the EFI partition with the command below:

mountvol P: /S

Note: The letter P was a suggestion that come from the link above but any other, as long as it is not already in use, would also work.

Then navigating inside the partition I was able to confirm that besides the WindowBootManager, ubuntu directory was also available (This meant finding the GRUB file associated with ubuntu inside the EFI partition. - \EFI\ubuntu\grubx64.efi).

After confirming that required boot file listed above existed, the boot order configuration needed to be changed so that GRUB could manage the boot process. For that I followed this other post answer which explained that executing the bcdedit executable enabled a way to assign other EFI entries as the initial boot manager. That was achieved by executing the command below.

bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi

Note that the path is the same we got from the previous step.

The command returned success. After that (until now) when I reboot I am redirected to Grub to select the operating system.

David avatar
cn flag
This answer may work today but what about later when the links you have included are gone? If they have information that is needed include in the answer not the links.

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