[Bug 1788630] Re: package grub-efi-amd64 2.02-2ubuntu8.3 failed to install/upgrade: installed grub-efi-amd64 package post-installation script subprocess returned error exit status 1

[Sandi Vujaković]

Since you say that you can't boot Ubuntu up on your computer without the
newer mainline kernels, but Ubuntu does not supply those kernels, I will
assume you used some boot parameter or another less than desirable
workaround for the issue until you installed the mainline kernels after
installing Ubuntu.

I am running mainline kernels on my laptop because of the wireless chip
(rtl8723be). With the LTS (4.15.xx.xx) kernels, it has weak WiFi signal
reception by default, but it is sort of remedied by passing a parameter
(rtl8723be.ant_sel=1) in the appropriate line of /etc/default/grub
before splash. However, that then leads to the same problems with
Bluetooth (can't play any sound through a Bluetooth speaker unless it's
touching a part of the laptop near the antenna). That issue is solved in
newer mainline kernels. I also need another parameter to boot the laptop
properly, even with mainline (iommu=soft). I am saying this as an
example in case you didn't use boot parameters, but would be willing to
try (better back up in case you don't get the right parameter on the
first try, since there is a small chance that files regarding the boot
sequence will get corrupted, had to reinstall because I tried to see if
the newer kernels did not need iommu=soft, after the third try some boot
files were dead, but /home was fine).

Tl;dr I have reasons to run mainline.

The way I got past it was to temporarily boot into the default kernel
for Ubuntu (LTS), got right up to the router because I couldn't be
bothered to type the parameter in, removed all of the mainline kernels
(tried with them there, but grub still threw a hissy fit), went through
with the upgrade, reinstalled the newest kernel from UKUU, restarted
with that kernel and patted myself on the back.

I hope this helps! (Newbie commenter prays that it's not too long for
whatever policy there might be for comments.)

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https://bugs.launchpad.net/bugs/1788630

Title:
  package grub-efi-amd64 2.02-2ubuntu8.3 failed to install/upgrade:
  installed grub-efi-amd64 package post-installation script subprocess
  returned error exit status 1

Status in grub2 package in Ubuntu:
  Confirmed

Bug description:
  On the update of grub-efi-amd64, it's now warning about unsigned
  kernels, which it was not doing before, and failing. However, before
  this update, the unsigned kernels were booting properly with Secure
  Boot enabled. I don't know what would make them unbootable now. The
  following message appears on upgrade:

   ┌───────────────────────────┤ unsigned kernels ├────────────────────────────┐
   │                                                                           │ 
   │ Cannot upgrade Secure Boot enforcement policy due to unsigned kernels     │ 
   │                                                                           │ 
   │ Your system has UEFI Secure Boot enabled in firmware, and the following   │ 
   │ kernels present on your system are unsigned:                              │ 
   │                                                                           │ 
   │  4.17.18-041718-lowlatency                                                │ 
   │  4.17.17-041717-lowlatency                                                │ 
   │                                                                           │ 
   │                                                                           │ 
   │ These kernels cannot be verified under Secure Boot.  To ensure your       │ 
   │ system remains bootable, GRUB will not be upgraded on your disk until     │ 
   │ these kernels are removed or replaced with signed kernels.                │ 

  Using the Ubuntu's default kernel is not an option to me, as it has
  bugs that weren't solved and make my notebook fail to boot.

  ProblemType: Package
  DistroRelease: Ubuntu 18.04
  Package: grub-efi-amd64 2.02-2ubuntu8.3
  Uname: Linux 4.17.17-041717-lowlatency x86_64
  ApportVersion: 2.20.9-0ubuntu7.2
  Architecture: amd64
  Date: Thu Aug 23 11:30:50 2018
  ErrorMessage: installed grub-efi-amd64 package post-installation script subprocess returned error exit status 1
  InstallationDate: Installed on 2017-06-13 (435 days ago)
  InstallationMedia: Xubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
  InvalidGrubScript: /etc/grub.d/40_custom
  ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.17.17-041717-lowlatency root=UUID=6b4ae5c0-c78c-49a6-a1ba-029192618a7a ro quiet kvm.ignore_msrs=1 kvm.halt_poll_ns=0 kvm.halt_poll_ns_grow=0 intel_iommu=on iommu=pt i915.enable_gvt=1 resume=UUID=0946602f-3ca2-4379-9012-7a5171928de7 ro mtrr_gran_size=2M mtrr_chunk_size=64M cgroup_enable=memory swapaccount=1
  Python3Details: /usr/bin/python3.6, Python 3.6.5, python3-minimal, 3.6.5-3ubuntu1
  PythonDetails: /usr/bin/python2.7, Python 2.7.15rc1, python-minimal, 2.7.15~rc1-1
  RelatedPackageVersions:
   dpkg 1.19.0.5ubuntu2
   apt  1.6.3ubuntu0.1
  SourcePackage: grub2
  Title: package grub-efi-amd64 2.02-2ubuntu8.3 failed to install/upgrade: installed grub-efi-amd64 package post-installation script subprocess returned error exit status 1
  UpgradeStatus: Upgraded to bionic on 2017-10-20 (307 days ago)

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