Serial IO

In situation where there is no keyboard or display, you can use serial cable communications.

Configure in grub.cfg

To configure serial input and output, in grub.cfg all you need to do is:

grub> serial --unit=0 --speed=9600

grub> terminal_input serial; terminal_output serial

The key commands are: serial, terminal_input, and terminal_output.

Once done, you can interact with GRUB via serial cable.

That's all about GRUB serial communications.