Early printk
From Attie's Wiki
Enabling EARLY_PRINTK
To enable the 'early' kernel messages do the following:
- Enable 'Kernel hacking' -> 'Kernel low-level debugging functions'
- Enable 'Kernel hacking' -> 'Kernel low-level debugging functions' -> 'Early printk'
- Add 'earlyprintk=ttyS0' or similar to your boot arguments
You will probably also have to select a serial port for the messages to appear (within the 'System Type' menu)