Comment 4 for bug 329644

Reverse-engineer the BIOS and fix the problem or replace it with a Linux BIOS. Note that "b" is a reboot command while "o" is power-off. The keys may be different if you are not using a QWERTY keyboard.

http://www.lesswatts.org/projects/acpi/
http://en.wikipedia.org/wiki/Magic_SysRq_key
http://www.coreboot.org
http://www.howtoforge.com/setting_up_a_serial_console