If you’re developing into the linux kernel but your system is crashing at boot, the boot_delay parameter may be usefull. If you added printk messages to see what happened just before, you may use the boot_delay=XXX options to add XXX milliseconds between each printk, and therefore allow you to see each messages if the messages pass through quickly.
To add this parameter, type “e” while the good entry is highlighted in the grub menu bootloader, and add boot_delay=XXX at the end of the line starting with “linux=”.
This is the “quick” solution. Other posts in this blog allows you to find other solution to make the console go through a serial link in a VM for instance.