There may be a time when one would want to hide boot messages that show up on the screen (or monitor or TV). The trick is to edit /boot/cmdline.txt file.

One may use the following command

sudo nano /boot/cmdline.txt

Then make the following changes to the file:

- Replace "console=tty1" by "console=tty3" to redirect boot messages to the third console.
- Add "loglevel=3" to disable non-critical kernel log messages.

After changing, to get to the console simply press Alt + F3 during or after boot. However, if text cursor needs to be hidden also then add “vt.global_cursor_default=0″ to the /boot/cmdline.txt file. In my case, I prefer to have text cursor as an indicator that it is actually booting.

Here is the content of my /boot/cmdline.txt

dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty3 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait logo.nologo loglevel=3

Information in this page is taken from http://www.raspberrypi.org/phpBB3/viewtopic.php?t=13807&p=153177