Comment 0 for bug 1848892

After upgrading to eoan today (via `do-release-upgrade -d`), my laptop failed to boot into the OS. I got the grub 2.04 screen (showing only Ubuntu), but selecting that gave me about 20 lines of "error: Unknown TPM error.", followed by "error: you need to load the kernel first" and no way to proceed/recover. Advanced options didn't work either. Dropping into the grub console and writing a simple command like `set root=(hd1,gpt5)` failed again with a TPM error. It goes without saying that booting had worked before with disco/grub 2.02.

As a workaround, I eventually managed to boot using an eoan live CD, chroot'ed into my system, added the `disco main` repo, and forcefully downgraded to disco's 2.02. After reinstalling grub to the efi partition, booting finally worked again (with grub 2.02).

lsb_release -rd
Description: Ubuntu 19.10
Release: 19.10

apt-cache policy grub-efi
grub-efi:
  Installed: 2.02+dfsg1-12ubuntu2
  Candidate: 2.04-1ubuntu12
  Version table:
     2.04-1ubuntu12 500
        500 http://ubuntu.inode.at/ubuntu eoan/main amd64 Packages
 *** 2.02+dfsg1-12ubuntu2 500
        500 http://ubuntu.inode.at/ubuntu disco/main amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: grub-efi 2.02+dfsg1-12ubuntu2
ProcVersionSignature: Ubuntu 5.3.0-18.19-generic 5.3.1
Uname: Linux 5.3.0-18-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu8
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sat Oct 19 23:20:07 2019
InstallationDate: Installed on 2017-03-05 (958 days ago)
InstallationMedia: Ubuntu 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215.2)
SourcePackage: grub2
UpgradeStatus: Upgraded to eoan on 2019-10-19 (0 days ago)