I made some progress: $ grub-probe -t device /boot/grub /dev/sda6
$ mount [...] /dev/sda6 on /boot type ext4 (rw,relatime) /dev/sda2 on /boot/efi type vfat (rw,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro) $ sudo ls /boot/efi/EFI/Ubuntu BOOTX64.CSV grub.cfg grubx64.efi mmx64.efi shimx64.efi $ dd if=/dev/sda bs=512 count=1 2> /dev/null | grep -q GRUB && echo "GRUB found" $ If I read these correctly, I do have files, but since the update no more MBR in /dev/sda. Is this observed correctly? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1898022 Title: grub upgrade 18.04->20.04 loses dual-boot to W10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1898022/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
