After a firmware update on my laptop, the Grub menu disappeared and I can only boot on Windows 10.

Machine configuration:

• Lenovo X1 Carbon Gen 7th shipped with Windows 10.


• I installed Ubuntu 18.04 with dual boot.


• Grub boot menu selection was working fine up to firmware update yesterday.


• The laptop is now booting directly to W10, without Grub menu showing up.

What I did:

• Try to upgrade grub using this post. Result was that a boot item was added in the BIOS. However when selected, it does nothing.


• Try to add a boot item using efibootmgr using following command line efibootmgr -c -d /dev/nvme0n1p1 -p 1 -l EFIubuntugrubx64.efi -L "GRUB ubuntu". I did that following this other post. Result was that a boot item was added in the BIOS. However when selected, it does nothing.


• Use boot-repair. I got following message: The boot of your PC is in EFI mode, but no ESP partition was detected. You may want to retry after creating a ESP partition (FAT32, 100MB~250MB, start of the disk, boot flag). Are you sure you want to continue anyway? And I didn't continue.

Ubuntu Pastebin is here. I notice in the Pastebin the message: Grub2 (v1.99-2.00) is installed in the MBR of /dev/nvme0n1 and looks at sector 2048 of the same hard drive for core.img, but core.img can not be found at this location. But I don't know how to use this information.

Ubuntu system is still on the disk:

nvme0n1                477G                                

├─nvme0n1p1 vfat       260M                                SYSTEM

├─nvme0n1p2             16M                                

├─nvme0n1p3           97.7G                                

├─nvme0n1p4 ntfs      1000M /mnt/boot-sav/nvme0n1p4        WinRE_DRV

└─nvme0n1p5 ext4       378G /mnt/boot-sav/nvme0n1p5        

at partition 5.

I have in my pocket: an old Clonezilla image of the full disk, a two days old backup... and the working laptop booting on W10 and on an Ubuntu USB stick.

Any suggestion on what to do? My target is to avoid reinstalling Ubuntu...

Thanks for your attention.