bootloader failed on /dev/sda

[Bill (franksmcb)]

T430N Ubuntu MATE 20.04 bootloader fails on /dev/sda in Legacy mode.

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: ubiquity 20.10.8
ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30
Uname: Linux 5.4.0-26-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu42
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.452
Date: Sat Jul 18 18:58:24 2020
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu-mate.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu-MATE 20.10 "Groovy Gorilla" - Alpha amd64 (20200718)
ProcEnviron:
 LANGUAGE=en_US.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 LC_NUMERIC=C.UTF-8
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)