grub-install fatal error during installation

[Hurky]

This happens both to the 21.10 and 20.04.3 versions

I install mdadm and assemble the RAID devices , then I start the installation and choose to install GRUB on the first drive /dev/sda , error says grub-install failed on /dev/sde

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubiquity 20.04.15.17 [modified: lib/partman/automatically_partition/question]
ProcVersionSignature: Ubuntu 5.11.0-27.29~20.04.1-generic 5.11.22
Uname: Linux 5.11.0-27-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.18
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.445.1
Date: Mon Jan 10 15:39:40 2022
InstallCmdLine: file=/cdrom/preseed/kubuntu.seed maybe-ubiquity initrd=/casper/initrd quiet splash --- maybe-ubiquity
LiveMediaBuild: Kubuntu 20.04.3 LTS "Focal Fossa" - Release amd64 (20210819.1)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

[Hurky (hurky)]

I fixed the problem, I have several mdadm RAID arrays but mdadm is not part of the installation and it looks like grub-install need that package as a dependency to identify the array.

The workaround:
Start the installation in 'Try Ubuntu' mode, don't fill up the user account information.
Open a terminal and chroot into /target
Install mdadm
Fill user data and continue installation.

Regards.