ubuntu 14.04 /boot partition deleted maybe after installing centos

[shubh9835]

hi! i had ubuntu 14.04 up and running on my laptop smoothly. for some reasons i wanted to setup a dual boot with centos. actually i had fedora in one of the partitions of which i thought to format and install centos. i think i made some mistake while installing centos which resulted me to end up with a scary grub rescue screen. so i tried to do repair the boot with boot repair software booting up a live usb of ubuntu which prompted me to uninstall grub. i could uninstall successfully but it could never reinstallit. so i thought of setting up ubuntu again on the partion with centos installed. i thought i'd be presented with a dual boot with my primary ubuntu but there was no dual boot.

i have my / directory of the primary ubuntu partition intact.
any help regarding fiing my primary ubuntu partition?
thanx



output for sudo fdisk -l

sudo fdisk -l



Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0xd9fa2484

Device Boot Start End Blocks Id System
/dev/sda1 2048 718847 358400 83 Linux
/dev/sda2 * 718848 204802047 102041600 83 Linux
/dev/sda3 204802048 716802047 256000000 7 HPFS/NTFS/exFAT
/dev/sda4 716804094 1953523711 618359809 f W95 Ext'd (LBA)
Partition 4 does not start on physical sector boundary.
/dev/sda5 716804096 1881358335 582277120 7 HPFS/NTFS/exFAT
/dev/sda6 1881360384 1882384383 512000 83 Linux
/dev/sda7 1882386432 1953523711 35568640 8e Linux LVM

Disk /dev/sdb: 7773 MB, 7773585408 bytes
255 heads, 63 sectors/track, 945 cylinders, total 15182784 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xc3072e18

Device Boot Start End Blocks Id System
/dev/sdb1 * 90 15182783 7591347 c W95 FAT32 (LBA)

Disk /dev/mapper/fedora-root: 28.9 GB, 28886171648 bytes
255 heads, 63 sectors/track, 3511 cylinders, total 56418304 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/fedora-root doesn't contain a valid partition table

Disk /dev/mapper/fedora-swap: 7532 MB, 7532969984 bytes
255 heads, 63 sectors/track, 915 cylinders, total 14712832 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/fedora-swap doesn't contain a valid partition table


/dev/sda2 being my root directory of primary ubuntu installation

[oldfred]

Best not to let any of the installs use LVM. I think your Centos install defaults to that. LVM is ok if you have the entire drive and then later want to move partitions around a lot. But it adds a level of complication.

You cannot share /boot partitions. The LVM will have to have one, but do not use /boot partitions with any other install. You may be able to share a data partition if all installs use UID 1000 for first or admin user.

Best to see details. With multiple installs or multiple drives always good idea to run this report to know what is where. I also run the bootinfoscript which is just a script and actually is the first part of Boot-Repair's summary report.
Post the link to the Create BootInfo summary report. Is part of Boot-Repair:
Boot Repair -Also handles LVM, GPT, separate /boot and UEFI dual boot.:
https://help.ubuntu.com/community/Boot-Repair

[shubh9835]

Best not to let any of the installs use LVM. I think your Centos install defaults to that. LVM is ok if you have the entire drive and then later want to move partitions around a lot. But it adds a level of complication.

You cannot share /boot partitions. The LVM will have to have one, but do not use /boot partitions with any other install. You may be able to share a data partition if all installs use UID 1000 for first or admin user.

Best to see details. With multiple installs or multiple drives always good idea to run this report to know what is where. I also run the bootinfoscript which is just a script and actually is the first part of Boot-Repair's summary report.
Post the link to the Create BootInfo summary report. Is part of Boot-Repair:
Boot Repair -Also handles LVM, GPT, separate /boot and UEFI dual boot.:
https://help.ubuntu.com/community/Boot-Repair

so i tried repairing with the boot-repair tool like a million times . i got a error everytime
here's the bootinfo summary http://paste.ubuntu.com/8419193/ . i would have reinstalled ubuntu but i have a lot of data which i don't want to loose.
btw the 4th line from bottom in the above report which says "Found Ubuntu 14.04 LTS (14.04) on /dev/mapper/fedora-root" thats not the ubuntu i want to be recovered. i installed it over the centos installation.
the primary installation exists on dev/sda2 . while installing ubuntu i configured only the "/ " and "/boot " partitions, i had made swap area before for fedora which i was using.
/dev/sda2 being the "/"

[shubh9835]

and now i get the error minimal bash-like shell .press tab....

[oldfred]

I am not seeing any kernels in sda1 or sda2?

Boot-Repair has an advanced uninstall of grub and full reinstall. I think that also updates to the latest kernel, or if not you need to include that as part of the reinstall of grub.

Boot-Repair finds various misc errors and reports those. Typically you will see it reinstalled grub with error code 0 and that is that it reinstalled grub correctly.
You do show a grub install to the partition boot sector of sda2. That will never be used, but do not install grub to partitions.
The os-prober looks for other installs so that is normal if it finds other installs and adds those to grub menu.

If Boot-Repair does not work then we can do the full chroot into your install to update it by totally uninstalling grub & reinstalling grub and new kernel.