Comment 44 for bug 1773457

My attempts to install 20.04 beta desktop or 18.04 LTS netinstall expert mode with full disk LUKS encryption failed.

1. Tried installing 20.04 Desktop ISO:
- selected manual partitioning
- created a single partition spanning the entire disk
- created a volume for encryption on the partition (LUKS)
- the LUKS was created, but there is no way to select the sda1_crypt volume as physical device for LVM. The option is absent from the list! So I go manually:
- exit out of the installation
- open a terminal, create the LVM VG and two LVs: root and swap
- start the installer again, now the LVM volumes are displayed
- select the root volume to be used as ext4 on /
- select swap LV to be used as swap
- proceed with installation normally, it finishes without errors.
- on reboot, grub drops to rescue shell, unable to find the "lvm" root disk. Probably due to missing GRUB_ENABLE_CRYPTODISK=y in /etc/default/grub.

2. Tried the 18.04 LTS netinstall booted over PXE:
- selected Advanced options, Expert Install
- used manual partitioning to create the same "MBR->partition1->LUKS->LVM->LVs root and swap" layout as above.
- installation proceeds fine until the "Install GRUB bootloader to the master boot record", where it errors: "grub-install /dev/sda failed". I try different combinations of grub options here, none work. So I'm unable to create a bootable system.

I could probably make the 2nd way work if I switched to the console, found out why it errors, fixed it, and installed it manually. But that's not expected of a normal user!

So now, in 2020, we have no way to install Ubuntu without unencrypted /boot. I have numerous machines that I either installed this way in the past, or manually copied over installations to hand-created LUKS and LVM, and with minor tweaks (chrooting into the copied system, adding GRUB_ENABLE_CRYPTODISK=y and tweaking fstab and crypttab) I can get them to boot fine.

I can swear this used to work on 14.04 and before, so this is a regression!