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My current situation;

I have tried to shrink down C: and add the resulting space to my Ubuntu partition. I've done this using Windows (which was probably the biggest mistake) and in the process I moved the "unallocated" space from the end of C: to the beginning of the Ubuntu Partition (the one with filesystem Ext4). My current Situation

Apparently Ubuntu does not boot anymore because the superblock is not found by GRUB. The partition is not mountable due to possible corruption on a live Ubuntu I bootet to. HELP

Question; How can I repair GRUB on my Ubuntu 20.04?

Edit; Boot Repair info

nonNumericalFloat
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  • You show UEFI system & UEFI installs, but installed a BIOS boot version of grub?? And your ESP is not showing the Windows UEFI boot files/folder? You need a Windows repair/recovery flash drive to fix that. I might try fsck on all ext4 partitions and then reinstall of grub in UEFI mode. How you boot install or repair flash drive UEFI or BIOS for both Ubuntu & Windows is then how it repairs. So only boot in UEFI mode. https://askubuntu.com/questions/642504/ubuntu-14-04-is-not-booting-normaly-after-a-manual-hard-boot/642789#642789 Then full reinstall of grub in UEFI boot mode using advanced mode. – oldfred Mar 11 '21 at 13:37

2 Answers2

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Re-allocate the memory to its original state and then try to boot into Ubuntu. Should work. Then Partition again using Gparted in Ubuntu.

Nabeel Jiwani
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Who believes this?! I was successfully by running fsck If you still can, only proceed with a Backup

1); List your disks with

sudo sfdisk -l

2); Find the one with your boot on it. In my case /dev/nvme0n1p6 (could be /dev/sdaX for you)

Device      Start        End          Sectors      Size   Type
/dev/nvme0n1p1      2048    923647    921600   450M Windows-Recovery
/dev/nvme0n1p2    923648   1126399    202752    99M EFI-System
/dev/nvme0n1p3   1126400   1159167     32768    16M Microsoft reserved
/dev/nvme0n1p4   1159168 817598519 816439352 389,3G Microsoft Basis
/dev/nvme0n1p5 817600512 818739199   1138688   556M Windows-Recovery
/dev/nvme0n1p6 818741248 974942207 156200960  74,5G Linux-Filesystem
/dev/nvme0n1p7 974942208 974991359     49152    24M BIOS boot
/dev/nvme0n1p8 974993408 976771071   1777664   868M Windows-Recovery

  1. Use fsck to check for errors

    sudo fsck /dev/nvme0n1p6

use additional -y flag after 'sudo' to try fix all errors immediatly.

  1. try booting

If you get something like;

Bad magic number in super-block while trying to open /dev/sda2
The superblock could not be read or does not describe a valid ext2/ext3/ext4

filesystem....you might try running e2fsck with an alternate superblock:


e2fsck -b 8193 <device>
or
e2fsck -b 32768 <device>
(Backup first - also any other OS partition)

You can try to

e2fsck -b 8193 /dev/sda

or

e2fsck -b 32768 /dev/sda
nonNumericalFloat
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