After Updating my 14.04 thro' internet, system is not opening.

[silver.bullet at zoho.com]

On Wed, 14 Oct 2015 08:06:59 +0530, Ramachandran Chidambaraiyer wrote:
>> 1. Boot your working Ubuntu 15.04.  
>> no such partition.  
>
>    entering rescue mode....
>     grub rescue>sudo -I
>    unknown command 'sudo'
>   grub rescue> mkdir /mojnt/rescue
>   unknown command 'mkdir'

If I understand correctly you mentioned that on your machine are Ubuntu
14.04 and Ubuntu 15.04 installed.

Is this correct?

If I understand correctly Ubuntu 14.04 is broken and Ubuntu 15.04 is ok?

Is this correct?

If so, then follow my advice and boot Ubuntu 15.04. Boot it normally,
not into rescue mode. Then boot the broken Ubuntu 14.04 in the
systemd-nspawn container in the way I explained you step by step.

If after the Ubuntu 14.04 update both Ubuntu are broken, the Ubuntu
14.04 and 15.04 install, then explicitly inform us about this now.

Or else ...

... is GRUB broken? Is it impossible for you to boot into any Linux?

"grub rescue>sudo -I" seems to be a GRUB prompt. That's the wrong place
to follow my advice. Btw. it would be "sudo -i" assumed you could boot
a Linux.

However, if GRUB already should be broken, then you need a live media.
At best a systemd based live media. I suspect the Ubuntu 15.04 DVD
provides live usage and systemd-nspawn. You also could use another
media without systemd, then you can't use systemd-nspawn, but need to
use chroot. The third option would be to install a third minimalist
Linux just to provide GRUB and nothing else.

I suspect that I already know the answer to my following question. Did
you backup your install and the MBR, assumed you should use MBR?

If something like this should happen on my machine, I simply restore
from a backup.

Regards,
Ralf