Can not install grub bootloader to /dev/sda

[ajgreeny]

Impossible to install grub bootloader into /dev/sda when installing the Xubuntu-20.10-beta-amd64.iso from today's daily download.

Installing as a VM in KVM/QEMU virt-manager

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: ubiquity 20.10.10
ProcVersionSignature: Ubuntu 5.8.0-21.22-generic 5.8.13
Uname: Linux 5.8.0-21-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu49
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.452
Date: Sun Oct 11 20:01:01 2020
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/xubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Xubuntu 20.10 "Groovy Gorilla" - Beta amd64 (20201011)
ProcEnviron:
 LANGUAGE=en_GB.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 LC_NUMERIC=C.UTF-8
RebootRequiredPkgs:
 linux-image-5.8.0-21-generic
 linux-base
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1899370

[ajgreeny (ajg-charlbury)]

zsync from the "current" to "pending" daily iso and choice of UEFI in the virt-manager configuration for creating the KVM virtual machine has now booted successfully.

I do not know if it was the move to the pending iso or to using UEFI firmware that has made the difference, but it appears that the iso file now defaults to UEFI when booted directly in KVM, probably also in VirtualBox but I've not used VirtualBox so not sure about that.

[Chris Guiver (guiverc)]

Possible duplicate of https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1897991