How to implement new features in existing bios?

Question

I wonder is it possible to implement new features in existing bios, in other words is there some libraries (like sdk) of motherboard which give you chance to make easy your own bios?

What mean "supported motherboard" - is that include libraries for developing or just mean that you can download latest update if exist?

To be more specific i will like to make in bios feature to wake up my computer if it's off at specific time. My motherboard is asrock. Do i have chance for develop my own timer features, or just can wait for product developer and pray that they make those feature?

Answer 1

Generally, the answer is "no". Most motherboard manufacturers license the BIOS source code from Phoenix/AMI/Insyde, and then tailor it to their specific motherboard implementation. The BIOS gets compiled to a binary, it is loaded into the motherboard flash chip, and that's it.

To modify the BIOS, you would need access to the BIOS source code. The motherboard manufacturer is unlikely to give that to you (they are probably under NDA). You could license the original source code from the BIOS vendor, but that is quite expensive (typically tens of thousands of $$$). Also, the source code from the BIOS vendor will be missing any motherboard-specific customizations.

Now, with the introduction of newer UEFI-based BIOSes, they have gotten a lot more extensible and standardized between vendors. It is now possible to develop pre-boot applications that live in the flash chip alongside the BIOS. However, the timer feature you are looking to implement is rather low-level, so this does not help you.