System not booting, grub rescue failing. Partition restoring?

Question

I kinda messed up... I was editing a partition from a external volume and I might have edited boot partition accidentally. My machine isn't able to boot, it says error: no such partition. entering rescue mode. grub rescue> (screenshot 1) I tried to list the partitions with grub rescue, but they seem empty?

System Info:
Ubuntu 16.04 running on amd64
trying to boot from SSD with boot and OS etc.
no backup of entire disk Everything worked fine before

Anyway I tried to
set boot=(hd1) set prefix=(hd1)/boot/grub insmod normal
which returns
Can't find /boot/grub/i386-pc/normal.mod (Beacause it's empty?) No fix I found so far helped.

I also tried starting with Ubuntu-live, where I can access the files of my SSD. There I opened gparted (screenshot 2) and used fdisk -l (screenshot 3), which tells me, there is no boot enabled partition. I suppose W95 Ext'd should usually be Linux, right? If so, is there a way to "convert" that table?

If you have other suspicions, please let me know.

Thx for any hints or resources that might be helpful!

Solution

Note that the issues you're experiencing apply to legacy mode booting. (Your partition table in gparted will say msdos) If you use GPT with BIOS or UEFI this doesn't apply.

error: no such partition. entering rescue mode. Implies that grub can not load modules and the file system on the same disk can no longer be found. In grubs terminology this is called stage 2. Either this is because your /boot partition was deleted or formatted. This also applies if your root was deleted containing a /boot directory.

You can try simply recreating the boot partition if it was deleted as unallocated space at the beginning of the disk of around 500MB was most probably your boot partition.

In gparted you can select the unallocated space and create a new partition but when creating it make the file system type unformatted. This is very important. It will default to taking up all the continuous free space and will be a primary partition. Free space preceding and following should be 0 After that click apply and after it loads it will detect that its ext3 or ext4 if that worked. This is not full proof and you may want to use testdisk to automatically find lost partitions instead.

Comments

[jdwolf]

Grub is not getting to a point where it can load modules therefor it won't detect most file systems. Hints the unknown file system errors. That means grub rescue isn't going to help you much. Use the live cd to recover.

[jdwolf]

Based on your gparted screenshot your boot partition is gone, its unallocated space now. While your system is on an LVM volume group in an extended partition. Note that the extended partition format comes from Windows hints the fs type is marked Windows 95 extended partition. You don't need to bother with the details other than this is used to "hold" more partitions than the usual 5 and you should only use gparted here to edit your partitions as its aware of extended partitions.

[jdwolf]

Chances are you only deleted the partition not the file system so recreating a partition that fills that first bit of unallocated space roughly 489 MiB should work. When creating it make the file system type unformatted This is very important. It will default to taking up all the continuous free space and will be a primary partition. Free space preceding and following should be 0 After that click apply and after it loads it will detect that its ext3 or ext4 if that worked.

[jdwolf]

I'm glad you're up and running again. Your question is so specific that I'm not comfortable making this an answer that can be applied generally. Yeah fully expected you'd still need to do grub rescue but it would at least have the ability to load modules.