A step by step tutorial for understanding Linux boot sequence
Boot Repair
Boots to a black screen
Error - File '/boot/grub/i386-pc/extcmd.mod' not found
Error - File '/boot/grub/i386-pc/normal.mod' not found
Error - ‘Initramfs Unpacking Failed’ Error Upon Booting
Fix Boot Problems
Free up space in /boot
GUID Partition Table (GPT)
List all installed kernels
Log boot messages
Master Boot Record (MBR)
Oh no! Something has gone wrong
Prevent UEFI Boot Issues
Speed up boot