apt update apt full-upgrade grub upgrades
from 2.02+dfsg1-20 to 2.02+dfsg1-20+deb10u1 no errors were spotted. When rebooted :- symbol grub_calloc not found Entering rescue mode grub rescue> I had to boot off a memory stick and then :- sudo -i mount /dev/sda5 /mnt grub-install --boot-directory=/mnt /dev/sda reboot This worked and the system now boots. /boot is the only ext type file system, the others are all handled by LVM Geoff