OMV Not booting after update

Hi,

I recently upgraded my setup from OMV 6 to OMV 7 and everything was working fine. This weekend, the NAS installed unattended upgrades (linux) and required reboot which I did saturday morning. Since that, the NAS didn't showed up on the network. I plugged a monitor on it and it's stuck at the GRUB bootloader (see attachments). Nothing works except CTRL+ALT+SUPPR

I managed to boot on OMV system with System Rescue live CD choosing "run existing OS", and everything looks OK but I don't know how to repair GRUB...

Hi,

I managed to run a live linux with boot-repair utility. The utility said it cannot help but generated the following report :

sda: ___________________________________________________________________________
File system:       iso9660    
Boot sector type:  Grub2 (v1.99-2.00)    
Boot sector info:  Grub2 (v1.99-2.00) is installed in the boot sector of sda and looks at sector 6353368 of the same hard drive for core.img, but core.img can not be found at this location.

full report : https://sprunge.us/XQICO2