I have a pc with dual-boot win10 / ubuntu 18.04
After a Windows update, i can't start Ubuntu, Grub starts in command-line mode.
I start pc with a live version of Ubuntu and these are my attempts:
fdisk -l /dev/sda
Disk /dev/sda: 489.1 GiB, 525112713216 bytes, 1025610768 sectors
Units...