Clean install 20.04.1 LTS to SDA formatted ext4; previous install 18.04.5 LTS partition removed priort to starting

[david clark]

Previous installation: Xubuntu 18.04.5 LTS 32bit kernel

- Removed SDA1 /root partition using installer
- Created new /root partition at SDA1
- Created EFI partition SDA5
- /Home partition on 500G HDD
- /storage partition on 1.2T HDD

After entering configuration information installer continued; towards the end error message "Executing 'grub-install /dev/sda' failed. This is a fatal error" and the installer wrapped up.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubiquity 20.04.15.2
ProcVersionSignature: Ubuntu 5.4.0-42.46-generic 5.4.44
Uname: Linux 5.4.0-42-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.4
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.445.1
Date: Wed Oct 21 14:59:58 2020
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/xubuntu.seed quiet splash ---
LiveMediaBuild: Xubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)