Comment 3 for bug 1666056

Thanks. A few things stand out here to me.

1) You're missing an "ubuntu" boot entry. That's the default one Dell populates when the machine is factory installed. It would have been pointed at shimx64.efi to chainload grubx64.efi.

Did you replace your SSD and manually reinstall at some point? Or is that the factory SSD?

2) There is actually a file \efi\boot\bootx64.efi on the ESP. Did you make that yourself?

3) I think if you run sudo update-grub you should get your missing 'ubuntu' boot entry replaced.

But so assuming you didn't replace the disk or tweak anything else a set of reproduce steps sounds like:
1) Start with preinstalled Dell 14.04.
2) Use Update manager to upgrade to 16.04.
3) From 16.04 do all the standard updates.
4) In software center apply BIOS update

That sound right?