The prompt presented during the grub update failed

[BertN45]

The grub update prompt, where you should select the boot device, did reject all options presented.
Good old
- update-grub and grub-install /dev/sda did work and rebooted the system nicely.

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: update-manager 1:19.04.8
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
Aptdaemon:

Architecture: amd64
Date: Sat Oct 12 20:11:09 2019
GsettingsChanges:

InstallationDate: Installed on 2019-10-08 (4 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Beta amd64 (20191008)
PackageArchitecture: all
SourcePackage: update-manager
UpgradeStatus: No upgrade log present (probably fresh install)