OCI : Grubby commands fail with error "/usr/bin/grub2-editenv: error: invalid environment block"

Applies to:

Oracle Cloud Infrastructure - Version N/A and later

Linux x86-64

Oracle Linux 8 – Oracle Linux 9

Symptoms:

Failed to change the default kernel

[root@xxxx ~]# grubby --set-default "/boot/vmlinuz-5.15.0-208.159.3.el8uek.x86_64"
grub2-editenv: error: invalid environment block.
The default is /boot/loader/entries/c20b6092d8ce4c58832f6d822e93dcec-5.15.0-208.159.3.el8uek.x86_64.conf with index 2 and kernel /boot/vmlinuz-5.15.0-208.159.3.el8uek.x86_64

Cause:

The file /boot/grub2/grubenv is either corrupted or not exactly 1024B (1K) in size.

Solution:

Confirm that grubenv file is pointing to the proper location

ls -l /boot/grub2/grubenv