OCI: Server Is Getting Stuck At "grub" Prompt After Reboot

APPLIES TO

Oracle Cloud Infrastructure - Version N/A and later
Linux x86-64

SYMPTOMS

After server reboot, the system is inaccessible because it is waiting for user intervention in Grub2's prompt:

         Minimal BASH-like line editing is supported. For the first word,
         TAB lists possible command completions. Anywhere else TAB lists
         possible device or file completions.
    
    grub> 

CAUSE

Corrupted /boot/efi filesystem which is pointed to /dev/sda1 device

cat var/log/messages | egrep 'Linux ver|sda1'Oct 30 22:32:49 hostname: Linux version 4.14.35-2047.541.4.1.el7uek.x86_64 (mockbuild@build-ol7-x86_64.oracle.com) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-16.0.3) (GCC)) #2 SMP Sat Oct 5 15:21:45 PDT 2024