/usr/sbin/grub-probe: error: failed to get canonical path of <root volume>

[Dave]

Using ZFS as boot drive. Error occurs on automatic snapshotting.

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: grub-pc 2.04-1ubuntu26.4
ProcVersionSignature: Ubuntu 5.4.0-42.46-generic 5.4.44
Uname: Linux 5.4.0-42-generic x86_64
NonfreeKernelModules: lkp_Ubuntu_5_4_0_42_46_generic_70 zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.8
Architecture: amd64
CasperMD5CheckResult: skip
Date: Fri Sep 18 07:37:31 2020
ErrorMessage: installed grub-pc package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2020-04-26 (145 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
ProcCmdLine: BOOT_IMAGE=/BOOT/ubuntu_tf2i6u@/vmlinuz-5.4.0-42-generic root=ZFS=rpool/ROOT/ubuntu_tf2i6u ro quiet splash
Python3Details: /usr/bin/python3.8, Python 3.8.2, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.18rc1, python-is-python2, 2.7.17-4
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.2ubuntu0.1
SourcePackage: grub2
Title: package grub-pc 2.04-1ubuntu26.4 failed to install/upgrade: installed grub-pc package post-installation script subprocess returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Julian Andres Klode (juliank)]

this seems to be a grub zsys support bug