do-release-upgrade misidentifies boot disk

[Ed Broadley]

I ran do-release-upgrade to update Ubuntu 18.04 to 20.04. This was done remotely, so it was important that the system could boot up again.

At the point it tries to install grub to the MBR it fails as it incorrectly identifies a USB connected drive as the boot drive. The USB connected drive is /dev/sda, whereas the boot drive, where the MBR needed to be updated, was /dev/sdb.

I do not know yet if the system can boot, but I ended up using a 3rd party app called boot-repair, which deals with this situation better by offering to install grub to the MBR of all detected disks.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubuntu-release-upgrader-core 1:20.04.32
ProcVersionSignature: Ubuntu 4.15.0-143.147-generic 4.15.18
Uname: Linux 4.15.0-143-generic x86_64
NonfreeKernelModules: lkp_Ubuntu_4_15_0_143_147_generic_81
ApportVersion: 2.20.11-0ubuntu27.17
Architecture: amd64
CasperMD5CheckResult: skip
CrashDB: ubuntu
Date: Thu Oct 14 08:38:56 2021
PackageArchitecture: all
ProcEnviron:
 TERM=screen.xterm-256color
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
Symptom: ubuntu-release-upgrader
UpgradeStatus: Upgraded to focal on 2021-10-14 (0 days ago)
VarLogDistupgradeXorgFixuplog:
 INFO:root:/usr/bin/do-release-upgrade running
 INFO:root:No xorg.conf, exiting