Few weeks ago i decided to upgrade my pc's ram modules, this upgrade was also requires bios update due to a bug of mainboard's (foxconn G41MXE) firmware. anyway downloaded the latest bios, replaced the hardware and spent few more minutes then changed the manufacturer's ugly oem logo. my plan was extraction of image file from bios dump and replace it with another picture which is fits byte to byte.
before that, surprisingly found a tool which can already do this process automatically within few minutes. if interested it's available in here: AMISuite.zip
i'm not sure its torrent alive now but at past year (2013) ami bios source code was leaked online from a taiwan based manufacturer's ftp server. also it's available in here. the code is completely ready to compile and well-documented. a great research material for students & modders. you cannot launch your own computer brand like tv show halt and catch fire but free to try non-commercial experiments with it.