Unable to boot from encrypted partition after fresh install of Ubuntu 16.04
Let me start by excusing myself, if some of the technical terms used are wrong. Although I do see myself as quite tech savvy, this is pretty far away from my usual territory.
I've been running with a partition layout like this for a while – an extended partition with 3 logical partitions in it:
A small, unencrypted partition for
Another, encrypted partition for
And the last partition, encrypted for
I initially based this layout more or less on the way the Ubuntu installer does it if I just let it do it for me, except that I have /home on a separate partition.
With the release of Xenial Xerus, I decided to do a clean installation. I also decided to wipe the existing partitions and recreate the same setup, but with different partition sizes. And so I did, by choosing the "Something else" option on the "Installation type" step in the installer. Installation went fine and all.
But upon boot, the splash screen stayed there for a long time. Where I would expect the passphrase prompt for the disk encryption key to appear, nothing happened. After some time, I was dropped to busybox with an
Since then, I've spend a whole day trying to find a fix. And I think I succeeded. But it seems like the installer is missing something. So let me try to explain what I did to make this work, hoping that it gives someone capable of fixing the installer a clue about what's wrong with it.
Several people on the internet suggested that I ran
initramfs prompt. But that command wasn't available. After doing more research on the interwebz, I managed to fix this by doing 3 things after mounting and chrooting the encrypted root partition from the Live USB:
1) I read somewhere that
cryptsetup would only be part of
/etc/crypttab was present. I followed a suggestion to manually edit the file
/etc/crypttab, which was missing(!), and entered the proper settings for my 2 encrypted partitions. This of course had to match with what the decrypted partitions were called in
2) Then I followed another suggestion to add the following modules to
aes-x86_64 sha512-ssse3 xts dm-mod dm-crypt
I have no idea whether this had any actual influence on the success, but – from the names of the modules – it sounds plausible that I needed at least some of those.
3) Finally, I ran
update-initramfs with some arguments along the lines of
-uck all (which seemed to form some quite appropriate words after hours of searching for answers without any luck at all).
After a reboot, I was finally prompted to enter the disk passphrase and eventually got to the login greeter. Phew!
Along the way, I also did several other things, but I tried to remember to always revert those changes if they did not work. Other things might have been changed manually, though, for this to work, but I believe that it was the things mentioned above that did the trick.
I also filed this as a bug report.
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