I also know how to use a USB flash drive. Another method is to use Chroot. Ithinkit should be repairable in this situation. Similar kernel issues have been fixed before:

After the USB flash drive enters the system, you can try:

sudo mount /dev/sda2 /mnt sudo mount --bind /proc /mnt/proc sudo mount --bind /sys /mnt/sys sudo mount --bind /dev /mnt/dev

The network seems to be set up like this

cp -L /etc/resolv.conf /mnt/etc/resolv.conf

Finally

sudo chroot /mnt

Sda2 should be changed to the same disk as Ubuntu.

Then again

sudo apt-get update sudo apt-get upgrade

Try it