installation crashes on grub install on the efi partition of a external ssd drive

[Agustin Araujo]

I made 4 partitions with gparted previous the Ubuntu 22.04.2 LTS installer using the Try Ubuntu on a USB pendrive. Had to install the mtools package (sudo apt-get install mtools) as the partition designated for the EFI (initially formatted as fat32 on gparted) wouldnt be recognized by the installer getting the warning about missing packages dosfstools and mtools, although after checking if packages existed dosfstools was initially there. Fixed the issue, or at least that is what I thought as the installation process kept going further than all failed attempts I went through before.
The rest of the partitions were EXT4, one for boot, root and home. Total of Ubuntu partitions summed 100GB all 4 in an extended partition. Following that I did the encryption for home and root partitions (sha 512)
Separately there was a ntfs partition not containing Windows OS but Windows folders with a whole bunch of music in mp3 format. On the Ubuntu installer this 150GB partition was not used. But the EFI partition was the only one which wouldnt show it is used space (unknown)
About at 80% of the installation grub-installer returns a fatal error related to the EFI partition (sda8)
My goal was to create a fully portable encrypted Ubuntu on 250GB removable SSD

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: ubiquity 22.04.19
ProcVersionSignature: Ubuntu 5.19.0-32.33~22.04.1-generic 5.19.17
Uname: Linux 5.19.0-32-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu82.3
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.470.2
CurrentDesktop: ubuntu:GNOME
Date: Fri Mar 10 14:06:56 2023
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 22.04.2 LTS "Jammy Jellyfish" - Release amd64 (20230223)
RebootRequiredPkgs: Error: path contained symlinks.
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)