Normally this is an easy task. You don't need a donator bios, the cpu-microcodes are available from Intel. I updated/added microcode with simply copy/paste in hex-editor. The microcode is never compressed or encrypted. You can use the tool "intelmicrocodelist.exe", which can search and display intel-microcode in all(?) bioses. It shows also the offset and size (in hex-code), so it is easy to replace parts of microcode. You will find few microcodes. Some boards only have two codes (laptops), other more then ten - and size of some code differs, that explains the different sizes of the microcode-part in bios.