Coreboot at Your Service!

<BayouConfig>
    <global>
        <timeout>5</timeout>
    </global>
    <payloads>
        <payload type="chooser" flags="default">
            <file>payloads/filo.elf</file>
        </payload>
        <payload type="chooser">
            <file>payloads/coreinfo.elf</file>
        </payload>
        <payload type="chooser" flags="default">
            <file>payloads/tint.elf</file>
        </payload>
    </payloads>
</BayouConfig>

The config file is fairly straightforward. The default payload starts after five seconds, and if nothing is chosen, the default is FILO. The other options are tint or coreinfo (Figure 4 shows it running in QEMU).

Next, make a directory for the payloads, put them into it, and then run make:

$ ls -l payloads

-rwxr-xr-x 1 ab users 47004 2009-01-03 11:59 coreinfo.elf
-rwxr-xr-x 1 ab users 71440 2009-01-09 21:35 filo.elf
-rwxr-xr-x 1 ab users 49298 2009-01-10 09:40 tint.elf
-rwxr-xr-x 1 ab users 74334 2009-01-10 19:22 seabios.elf

$ make

Now, run image in QEMU, and you can play Tetris from the BIOS (Figure 5).

Figure 5. Take a rest—Tetris running from the BIOS.

Coreboot allows you to replace your motherboard's proprietary BIOS with a free and open-source BIOS. Coreboot already can boot Windows XP and Windows Vista as well as FreeBSD, Plan9 and, of course, Linux. Operating systems can be started from local disks, from a network connection or even from a serial port. Although it's not yet feature-complete, coreboot provides a base for building more flexible BIOSes.