Am I doing something wrong installing using LUKS in dual boot?

I've got a dual boot system with Win 8 installed, I'm re-installing ubuntu 13.10 along side to enable full disk encryption, following this guide almost to the letter: How can I install Ubuntu encrypted with LUKS with dual-boot? The only difference is that I don't create a new boot partition (there is already an EFI boot partition), and I use two partitions for home and / (probably pointless as they're both in the same LUKS container)

Creating the LUKS container and partitions seems to go fine (no errors reported certainly). So I finish the graphical installer, but it fails with: The 'gub-efi-amd64-signed' package failed to install into /target/. Without the GRUB boot loader, the installed system will not boot.

I've tried this twice now, and got the same thing both times.

extra details

The machine is a Dell xps 15 (l521x) I'm using an ubuntu 13.10 live dvd. I previously used the same dvd to install next to the same windows install, just without the LUKS stuff, and it worked with no problems.

EFI - fast boot and secure boot are disabled.

I'm also a relative linux newb, and have never dealt with EFI or disk encryption before.

This question has a similar problem, but on 12.04, and without LUKS.


The EFI System Partition (ESP; what Ubuntu and you refer to as an "EFI boot partition") is not exactly the same as a Linux /boot partition. The ESP holds EFI boot loaders and associated files. The /boot directory (or partition, if it's a separate partition) holds the Linux kernel. I'm not a LUKS expert, but presumably the Linux kernel is kept outside of LUKS because that enables the boot loader to read it without having to understand LUKS encryption. In your configuration, /boot is encrypted, so the boot loader would need to understand encryption in order to work. That could be why it's failed.

In other words, try again, but this time, do create a separate /boot partition in addition to the ESP.

  • Awesome, I'm trying that now. Quick question, what size should the boot partition be? The guide says (a few hundred megabytes), but in general his sizes seem very small (about 8gb total for the lot) – Andrew M Oct 29 '13 at 0:07
  • Worked - Thanks :) I can now boot to linux or windows, and the partitions are encrypted. Grub isn't working, but that's another question! – Andrew M Oct 29 '13 at 1:15
  • I'm glad you've gotten it working. As to sizes, a 200-500MiB /boot partition is generally big enough. Mainly it holds the kernel and initrd file, and the two combined generally consume about 20MiB; however, over time you're likely to collect several sets of these files, so they can consume over 100MiB. The Linux base installation (not counting /home) typically consumes about 5GiB, but can grow larger if you install lots of software. An 8GiB allotment is barely adequate for this. User files (in /home) add to this, of course. – Rod Smith Oct 29 '13 at 15:10

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