Grub installs on wrong device on custom partition setup

[Simon Chopin]

I have a fairly complex setup on my desktop, with the following drives:

* a Samsung NVMe drive with a Ubuntu Focal Desktop install
* a Crucial NVMe drive with a Ubuntu Jammy Desktop install
* a Samsung SATA SSD with Windows
* a USB SSD that I use to do test installs of Ubuntu.

That last drive had a partition scheme with a EFI partition and an ext4 partition. I selected a custom setup, changed the boot drive from the default (the Samsung NVMe drive) to the USB SSD, and simply marked the ext4 partition as to be formated and mounted as /, and then proceeded with the rest of the install.

When I booted up and selected the ubuntu EFI entry from the USB SSD, it was a broken Grub (presumably leftover from previous tests). However, the Samsung NVMe Ubuntu entry would take me to a grub configured to boot on my brand new Jammy 22.04.1 install, instead of my previous Focal entry.

I suspect that subiquity never actually registered that I changed the boot drive.

I reproduced the issue reliably with the candidate 22.04.1 image from 2022-08-02, and am fairly sure I saw the same issue with the 20.04.3 image, I just didn't take the time to investigate.

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: ubiquity (not installed)
ProcVersionSignature: Ubuntu 5.15.0-43.46-generic 5.15.39
Uname: Linux 5.15.0-43-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.1
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Tue Aug 2 16:16:54 2022
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
InstallationDate: Installed on 2022-08-02 (0 days ago)
InstallationMedia: Ubuntu 22.04.1 LTS "Jammy Jellyfish" - Release amd64 (20220801)
SourcePackage: ubiquity
Symptom: installer
UpgradeStatus: No upgrade log present (probably fresh install)

[Simon Chopin (schopin)]

Also, /etc/fstab on the new Jammy install mounts the wrong drive to /boot/efi (the Samsung NVMe)

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1983384