Is it possible to regenerate grub2 at sdc1 ?

[c3p0]

I have 3 physical bootable storages.
sda: Not Linux
sdb: Linux
sdc1: LEAP 42.1 openSUSE
sdc4: just installed Linux - damaged the grub2 of sdc1.

I used sdb - grub2 for loading another Linux at sdb. Used the command:

sudo update-grub

and then it is possible to load LEAP 42.1 openSUSE at sdc1 and the new Linux at sdc4.

Is it possible to regenerate the grub2 at sdc1 ?

[gogalthorp]

EFI or MBR boot??

[c3p0]

EFI or MBR boot??

Sorry, I don't know that ....

[gogalthorp]

details will make a difference on how to proceed

[c3p0]

Is the following information useful ?

Loading Operating System ...
GRUB loading.
Welcome to GRUB!

error: file '/boot/grub/i386-pc/normal.mod' not found
Entering rescue mode...

grub rescue> ls(hd3,1)/
./ ../ lost+found/ grub/ System.map-3.19.0-32-generic abi-3.19.0-32-generic 
config-3.19.0-generic memtest86+.bin memtest86+.elf memtest86+_multiboot.bin 
vmlinuz-3.19.0-32-generic initrd.img-3.19.0-32-generic

[gogalthorp]

If you have stuff in lost and found then you have a file system error. From rescue disk run fsck on the root partition. Note lost files may not be complete or continues so if binary it is unlikely to be able to recover such files. So full restore is questionable. Maybe you are lucky maybe not

Also from rescue disk run smartctl pointing to the drive in question.

If running BTRFS maybe just maybe you can boot to an earlier snapshot

Still unknown how you boot. Do you have a older BIOS or the newer UEFI. If UEFI then it still maybe legacy MBR boot dependent on how you installed.

[c3p0]

I believe am lucky, because all the lost+found directories are empty.
Then I explored all the /boot/ directories and found that only the sdc4's /boot/grub/ does not contain subdirectories as another ones.
Then as SU I copied with all the subfolders /boot/grub2/ from sdc1 to sdc4 as /boot/grub/
After restart the PC it boots correctly, without grub rescue> at all, but there is not the newest installed Linux as an option in grub-list.
At least I copied the file grub.cfg from sdb to sdc4, because it contains all the available Linuxes.
After restart of the PC all the Linuxes are in sdc4's grub-list for start.
I have an older BIOS and probably I have MBR-boot ....
Thank you.