Problem MBR - hang on boot with GRUB.

English Install/Boot/Login
1

Greetings!

I want to create an identical backup-system from an opensuse-42.1.
The system is installed on a 500GB disk /dev/sda.
/dev/sda1 is mounted as /boot
/dev/sda2 is swap
/dev/sda3 is /

The backup medium is a 1TB-USB drive mounted on /mnt.
To backup the MBR I type
dd if=/dev/sda of=/mnt/mbr.img bs=512 count=1
To backup the system I type:
dd if=/dev/sda1 of=/mnt/sda1.img
dd if=/dev/sda3 of=/mnt/sda3.img

The target system also has a 500GB disk installed.
I boot ‘gparted’ from a life usb-stick, and the 1TB-USB drive is mounted on /mnt.
lsblk [FONT=arial]shows /dev/sda[/FONT]

To resotore MBR:
dd if =/mnt/mbr.img of=/dev/sda bs=512 count=1
After this and a refresch of gparted it shows the partitions:
/dev/sda1
/dev/sda2
/dev/sda3
Now I restore the system:
dd if=/mnt/sda1.img of=/dev/sda1
dd if=/mnt/sda3.img of=/dev/sda3

I also set the UUID of all 3 target partitions to the same value as on the source partitions.

Now I reboot the system and I see

GRUB

in the upper left corner of the screen and thats it.
The system does not boot.

Any hints what I’m missing?

Thanks for reading
Wolf

2

By default UUID is used to identify partitions these can change sometimes so look at /etc/fstab and /dev/disk/by-uuid and see if the ids match

3

Yes, I’ve checked it: target UUID is the same as source UUID.

I also set the UUID of all 3 target partitions to the same value as on the source partitions.

as I stated in my post.

4

If GRUB was installed in MBR, the actual binary is located in post MBR gap which is outside of any partition. You did not preserve this space.

5

With dd if=/dev/sda of=mbr+boot.img bs=64KB I saved the first 64 KiB of the source device and restored it on the target device.

Now the system boots - then loops with immediately rebootig…

What is the appropriate procedure to backup mbr and grub bootcode?

6

If system boots then bootloader obviously worked and you have some other problem.

7

Issue solved with using bs=1M for saving mbr+boot code.