Ubuntu Server 20.04 installation to drive with BIOS set to legacy mode results in non-booting drive

[Michael Lueck]

I opened a forum ticket about this observation here:

"Unable to boot from HDD 20.04 installed with BIOS in Legacy mode"
https://ubuntuforums.org/showthread.php?t=2455005&p=14015093

I suspect there might be a defect in Ubuntu Server 20.04 ISO. I was loading it onto a ThinkPad to test out the new Ubuntu Server LTS release. I had the ThinkPad BIOS set to boot from legacy mode disks, all UEFI disabled.

The partitions Ubuntu Server 20.04 created for me were as follows:

Disklabel Type: gpt
sda1 BIOS Boot
sda2 Linux filesystem (which I selected xfs)

The system failed to boot from the HDD. When trying to boot from the system's HDD, I only am able to get the ThinkPad "Boot Menu / Application Menu" screen to come up. Selecting ATA HDD0 loops back around to the same menu.

It was suggested that Ubuntu 20.04 really prefers to boot from drives in UEFI mode. I changes the BIOS settings, wiped the disk during another test installation. This time the partitions the installer created were as follows:

Disklabel Type: gpt
sda1 EFI System
sda2 Linux filesystem (which I selected xfs)

And the system does boot from the HDD now.

So is this a defect in the installer for Ubuntu Server 20.04 that it does not produce a bootable drive when the computer BIOS is set to legacy boot mode?

I was expecting to see the legacy boot partition table type not be a gpt partition table. Might that have something to do with the failure to boot?

I think the fact that for the legacy boot installation, Ubuntu Server did at least create a first partition of type "BIOS boot".

<><><><>

I tried the same installation on the same ThinkPad from the ubuntu-20.04.1-live-server-amd64.iso disk. Same results as before.

Looks like Ubuntu Server has a defect booting from disks where the BIOS is set to legacy mode.

This is not broken in Xubuntu 20.04 installation.

Logging an Ubuntu Server installer defect.

<><><><>

Xubuntu 20.04 does NOT have this same defect. Xubuntu 20.04 boots properly when installed to systems with the BIOS set to legacy mode for the hard drive access setting.
---
ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: pass
DistroRelease: Ubuntu 20.04
InstallCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-26-generic root=UUID=468b6f29-36bc-4b5f-b089-3f3ad0f91cf4 ro
InstallationDate: Installed on 2021-01-18 (0 days ago)
InstallationMedia: Ubuntu-Server 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
Package: ubiquity (not installed)
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30
SourcePackage: ubiquity
Tags: focal uec-images
Uname: Linux 5.4.0-26-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lxd plugdev sudo
_MarkForUpload: True

[Chris Guiver (guiverc)]

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

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

The following needs to be performed, HOWEVER you have filed this bug against `ubiquity` (ie. the desktop installer), and NOT a server installer (`subiquity` (https://ubuntu.com/blog/tag/subiquity) or `debian installer`).

If it's a desktop installation problem, you can run apport-collect now, however if it's a server installation, the package should be changed first.

(you do mention 20.04.1-live-server-amd64.iso which uses subiquity. If you run the `ubuntu-bug` on the system in future, the correct package will be detected by your system)

--

Please execute the following command only once, as it will automatically gather debugging information, in a terminal:

apport-collect 1912276

[Michael Lueck (mlueck)]

apport information

[Michael Lueck (mlueck)]

apport information