Bios passwords can be more formidable then simply toggling f2.f8 del or space bar in some instances there are options to require a password to change the boot device setting or even any modification to the start up routine there are however a few clever uses of python and some minor scripting foo that can conjure up backdoor code . The credit is 100% the result of dogbert's blog posts . These are some very useful links that require careful reading for success. See . http://dogber1.blogspot.com/2009/05/table-of-reverse-engineered-bios.html . http://dogber1.blogspot.com/ .
https://github.com/dogbert/bios-pwgen . hackaday.com/2010/10/07/bios-password-cracking/