Ubiquity creates useless ESR (EFI) partition on Bios system

[Jeremie Tamburini]

Ubuntu 21.04 - 16/4 daily build - Ubiquity 21.04.15

Even on computers with old BIOS an ESR (EFI) partition will be automatically created when installing Ubuntu using one of the automatic options like "Erase disk and install Ubuntu", "Install Ubuntu alongside other system", etc..

This should not happens. No ESR partition should be created on systems with old BIOS.

In this case:
- 2 partition where already existing:
  - /dev/sda1 Ext4 with Ubuntu 21.04 already installed
  - /dev/sda2 Ext4 empty
- Performed the "Install Ubuntu alongside other system" install option".
- After install:
  - /dev/sda3 Fat32 ESP
  - /dev/sd4 extended
  - /dev/sda5 Ext4 with new Ubuntu 21.04

I've set just 2 existing primary partition because if the installer doesn't find a primary partition for ESR, installation will fail.... and that's another bug, see bug #1924823

In this case installation will succeed, but just think about all the systems with old BIOS that are already using 3 primary partitions and there's no extra primary partition for ESR.. in that case installation fails.

ProblemType: Bug
DistroRelease: Ubuntu 21.04
Package: ubiquity 21.04.15
ProcVersionSignature: Ubuntu 5.11.0-14.15-generic 5.11.12
Uname: Linux 5.11.0-14-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu65
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.461
CurrentDesktop: ubuntu:GNOME
Date: Sat Apr 17 16:04:41 2021
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 21.04 "Hirsute Hippo" - Beta amd64 (20210416)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
RebootRequiredPkgs:
 linux-image-5.11.0-14-generic
 linux-base
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

[Julian Andres Klode (juliank)]

This is a feature, not a bug.

[Jeremie Tamburini (jeremie2)]

> juliank
> This is a feature, not a bug.

It's what I thought once I was aware of all these troubles:
https://discourse.ubuntu.com/t/groovy-to-use-grub2-for-booting-installer-media-in-any-modes-on-all-architectures/16871/34

But it looks like nobody knew about EFI partition with BIOS and I've been asked to file a bug report about it.

Fortunately year after year we are going to have less old computers based on old BIOS and also Ubuntu 20.10 and 21.04 are not LTS version and therefore not so popular.
But a feature like this should have been "loudly" communicated to all users before landing into the installer, after decades with no need of EFI partition with BIOS. And should have been also bullet proof tested before landing to users.