Re: Destroyed Entries at /dev/sda - boot not possible anymore

[Andrei Borzenkov]

On Tue, Mar 31, 2015 at 4:17 PM, Stefan Lamby <address@hidden> wrote:
>> > OK, so grub.cfg on /dev/sda1 refers to /dev/sdb2. Am I right that
>> > /dev/sda1 is your original /boot?
>
> Yes, sda is the hd used originally.
>
...
>
> address@hidden:~# mount -r /dev/sda2 /mnt
> address@hidden:~# ls -l /mnt/
> total 138250
> -rw-r--r-- 1 root root  1207386 Jan 15 18:22 abi-3.16.0-30-generic
> -rw-r--r-- 1 root root  1207327 Mar 10 21:12 abi-3.16.0-31-generic
> -rw-r--r-- 1 root root  1207327 Mar 13 11:12 abi-3.16.0-33-generic
> -rw-r--r-- 1 root root   171768 Jan 15 18:22 config-3.16.0-30-generic
> -rw-r--r-- 1 root root   171802 Mar 10 21:12 config-3.16.0-31-generic
> -rw-r--r-- 1 root root   171827 Mar 13 11:12 config-3.16.0-33-generic
> drwxrwxr-x 2 root root     1024 Feb 21 18:27 efi
> drwxr-xr-x 5 root root     1024 Mar 24 09:41 grub
> -rw-r--r-- 1 root root 29216458 Feb 21 19:04 initrd.img-3.16.0-30-generic
> -rw-r--r-- 1 root root 29225033 Mar 15 08:53 initrd.img-3.16.0-31-generic
> -rw-r--r-- 1 root root 29232450 Mar 24 09:41 initrd.img-3.16.0-33-generic
> drwx------ 2 root root    12288 Feb 21 18:27 lost+found
> -rw-r--r-- 1 root root   176500 Mar 12  2014 memtest86+.bin
> -rw-r--r-- 1 root root   178176 Mar 12  2014 memtest86+.elf
> -rw-r--r-- 1 root root   178680 Mar 12  2014 memtest86+_multiboot.bin
> -rw------- 1 root root  3511040 Jan 15 18:22 System.map-3.16.0-30-generic
> -rw------- 1 root root  3511419 Mar 10 21:12 System.map-3.16.0-31-generic
> -rw------- 1 root root  3512061 Mar 13 11:12 System.map-3.16.0-33-generic
> -rw-r--r-- 1 root root  6345120 Feb 21 18:33 vmlinuz-3.16.0-30-generic
> -rw-r--r-- 1 root root  6347032 Feb 19 16:18
> vmlinuz-3.16.0-30-generic.efi.signed
> -rw------- 1 root root  6346448 Mar 10 21:12 vmlinuz-3.16.0-31-generic
> -rw------- 1 root root  6348376 Mar 15 08:53
> vmlinuz-3.16.0-31-generic.efi.signed
> -rw------- 1 root root  6348624 Mar 13 11:12 vmlinuz-3.16.0-33-generic
> -rw------- 1 root root  6350552 Mar 24 09:41
> vmlinuz-3.16.0-33-generic.efi.signed
> address@hidden:~# ls -l /mnt/grub/
> total 2381
> drwxr-xr-x 2 root root    1024 Feb 21 18:40 fonts
> -r--r--r-- 1 root root    9790 Mar 24 09:41 grub.cfg
> -rw-rw-r-- 1 root root    1024 Mar 29 12:46 grubenv
> drwxr-xr-x 2 root root    1024 Feb 21 18:40 locale
> -rw-r--r-- 1 root root 2405285 Feb 21 18:40 unicode.pf2
> drwxr-xr-x 2 root root    8192 Feb 21 18:40 x86_64-efi
>
> Yes, those partitions sda1,2,3 are the ones originally used. The ubuntu
> installer
> has overwritten sda even it was told to use sdb

I do not know if it actually overwrote sda. Last change was apparently
24 March when new kernel 3.16.0-33 was installed. Did you update your
"original" installation on this day?

Rather it looks like second installation overwrote bootloader in
/dev/sda1. So try following

1. boot into GRUB CLI with single disk, with USB
2. Execute

insmod part_gpt
insmod ext2
chainloader (hd0,gpt2)/grub/x86_64-efi/core.efi
boot

With some luck you should get your original grub menu.