lubuntu 18.04 install failed at Grub installation stage

[Doug Nelson]

Installation (minimal not full) was sucessfull on same model number, part number and product id dell wyse thin client, both had amd 1.4 Ghz processor, 2GB RAM and 8GB FLASH D. Both had the same BIOS as well.
Could this be a hardware issue (the FLASH Drive) causing this failure?
I also tried boot-repair without success, as this App asked for Secure boot to be turned off but this is not in the BIOS of the 5010 thin client.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.14.15
ProcVersionSignature: Ubuntu 5.4.0-42.46~18.04.1-generic 5.4.44
Uname: Linux 5.4.0-42-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.16
Architecture: amd64
CasperVersion: 1.394.3
Date: Sun Sep 26 03:36:49 2021
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/lubuntu.seed boot=casper only-ubiquity quiet splash ---
LiveMediaBuild: Lubuntu 18.04.5 LTS "Bionic Beaver" - Release amd64 (20200806.1)
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)

[Chris Guiver (guiverc)]

Thank you for taking the time to report this bug and helping to make Ubuntu better.

Don't forget Lubuntu was a flavor of Ubuntu, where flavors only came with 3 years of supported life. Ubuntu 18.04 Desktop, Server & Cloud products came with five years of support.

- https://lubuntu.me/bionic-eol/
- https://fridge.ubuntu.com/2020/08/14/ubuntu-18-04-5-lts-released/

I don't see any flash-media issue (ie. squashfs errors), but grub-installer issues.