Some good documentation about mod/bios topics

Hi,

Some days before, when I was looking for some kind of mod in order to make my mboard boot from pci-e, I met this forum.
I made a request for a way to mod my board bios, and I’m still waiting for someone to help me. But I think that maybe my request is too obvious, or maybe it doesn’t have any sense. The thing is that now I’m trying to get some more knowledge about bios/efi options and mods.
I’ve been having a look to some of the most important posts from this forum, but it seems that I need to start from some more elemntal concepts in order to understand most of the vocabulary and concepts written in here.
I’d like to ask you for some help in order to get some good documentation about bios modding and options. I think it’s a very interesting topic.
So, in order to start, I would like to know a place where I could get some information about the different options available in the huge wold of the bios/uefi. For example, I’d like to understand what the opRom is, and that kind of concepts.

As I can see, here are quite a lot of people who have a big knowledge of these topics, so I’m asking your help to find a good place to start studying.

I’d apreciate yoy help very much.

Thank you in advance!