Comment 9 for bug 1256730

Ok I have booting working now. I can almost describe the steps...

I followed http://blog.nguyenvq.com/blog/2014/07/25/upgrading-ubuntu-12-04-to-14-04-breaks-encrypted-lvm/ and created /etc/initramfs-tools/conf.d/cryptroot (did not exist before creating). That solved the issue. However, I finally noticed my /etc/fstab's / entry pointed to the UUID of /dev/sda4, not the UUID of /dev/mapper/xyz. After changing the UUID to /dev/mapper/xyz, neither /etc/initramfs-tools/conf.d/cryptroot or the forcecryptsetup were needed anymore.

To make the story complete, right after I had really upgraded from 14.04 to 16.04, my system did not boot with any kernel, new or old, and I needed to boot from USB and install cryptsetup + mount manually. I tinkered around /etc/default/grub and /etc/fstab until I got it booting... I was not using UUIDs in 14.04, that much I remember, and I think I did not have the cryptdevice option in grub.

It's so complex topic I really have no good ideas what should be made more robust. Obviously something broke (for me) during upgrade, and my fix to that broke further initrd creations.