Right so I received my Dell XPS 13 (my goodness, it's beautiful) and have proceeded to spend the whole of yesterday and today so far trying to install 18.04 on it (it comes with 16.04).
It would install, reboot, & throw me in the Grub command line. Tried with FDE & without. Same.
Can now manually get it to boot from grub with:
> set root=(hd0,2)> linux /vmlinuz> initrd /initrd.img> boot
It boots but it's back to grub next reboot.
Tried sudo update-grub && sudo grub-install
* Typo, the second line should read:
> linux /vmlinuz root=/dev/nvme0n1p2
(If you forget the root bit, it doesn't boot anyway.)