Ubuntu 16.04 not bootable after system update

I installed a system update today, which included updating something related to the bios. I have a machine with linux and windows and I used grub to choose the OS to boot into. After the update, the grub screen doesn't show anymore and everything I get is a screen asking me to perform MOK management and the options to continue boot, enroll key from disk or enroll hash from disk. If I continue boot, I end up in Windows.

When I press F12 during startup and go into the boot menu, I can choose only from Windows Boot Manager and the Linux-Firmware-Updater \fwupx64 (which brings me back to the MOK screen). What do I have to do in order to get the normal booting routine using grub back so that I can use my Ubuntu again?

Solution 1:

Ok I solved my problem, and I'm writing an answer in case anyone else had the same problem.

What happened was that the update replaced the grub bootloader with this Linux-Firmware-Updater. All I had to do was to go into the BIOS settings and add a boot option under Boot Sequence. I choose grubx64.efi which is under EFI/ubuntu/. I placed it as the first boot option and everything was back to normal.

Solution 2:

I had the same exact problem with my Dell Precision 5510 after a firmware update via Ubuntu 16.04. Boot device was not recognized and Dell's memory check and hardware tests kept running instead of my operating system.

Solution: Thanks so much @Christoph Pohl!

I wrote up Christoph's solution below to help those that are less familiar:

1. On boot-up when Dell logo is present press F2 for BIOS
2. In BIOS navigate through "general" until you find "Boot Sequence"
3. Click on "add boot option"
4. Enter name for your new boot option
5. Click on "..." and navigate to EFI/ubuntu/grubx64.efi
6. Apply
7. Ensure your new boot option is checked on the left
8. Organize boot order on right via up/down arrows so that its on top
9. Apply/Save/Reboot

This was a real life-saver as my USB drive with live-boot was literally just formatted!