EXT4 filesystem fails to be mounted with error: unknown filesystem type 'ext4'

Issue

• During the reboot, EXT4 filesystem fails to be mounted with error below in journalctl log:

Nov 06 14:33:58 vtuvaina014 mount[748]: mount: unknown filesystem type 'ext4'
Nov 06 14:33:58 vtuvaina014 systemd[1]: boot.mount mount process exited, code=exited status=32
Nov 06 14:33:58 vtuvaina014 systemd[1]: Failed to mount /boot.
-- Subject: Unit boot.mount has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit boot.mount has failed.
-- 
-- The result is failed.