[Bug 1898022] Re: grub upgrade 18.04->20.04 loses dual-boot to W10

[Mate Kukri]

is the windows installation also uefi? (dual booting a bios install of
windows from uefi grub is not possible, grub and windows have to match
for that to work)

what is in /etc/default/grub and /boot/grub/grub.cfg?

did you run update-grub? what was its output?


** Changed in: grub2 (Ubuntu)
       Status: New => Incomplete

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Title:
  grub upgrade 18.04->20.04 loses dual-boot to W10

Status in grub2 package in Ubuntu:
  Incomplete

Bug description:
  (Summary says it:)

  Upgraded by dual-boot kubuntu 18.04 to kubuntu 20.04. After the restart, dual-boot was gone, and it boots directly into kubuntu. 
  I guess it is a problem with grub, because the boot menu doesn't show. However, the 'lenovo' shows trice, while it used to show once with 18.04; followed by the grub boot menu. 

  I guess that the MBR was written into haywire?

  ProblemType: Bug
  DistroRelease: Ubuntu 20.04
  Package: grub-efi-amd64-bin 2.04-1ubuntu26.4
  ProcVersionSignature: Ubuntu 5.4.0-48.52-generic 5.4.60
  Uname: Linux 5.4.0-48-generic x86_64
  ApportVersion: 2.20.11-0ubuntu27.9
  Architecture: amd64
  CasperMD5CheckResult: skip
  CurrentDesktop: KDE
  Date: Thu Oct  1 11:34:39 2020
  InstallationDate: Installed on 2019-03-14 (566 days ago)
  InstallationMedia: Kubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
  SourcePackage: grub2
  UpgradeStatus: Upgraded to focal on 2020-09-29 (1 days ago)

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