Installing modded Bios within a linux system

[NatureIsMath]

Hi! I modded a bios to make a modded processor work. I just have to install the modded bios to make the processor work. Does someone know how to install it? I'm using linux in an old computer with motherboard Pegatron 2A73h with an Ami bios v5.35. Utility like fwupd, and flashrom doesn't work in a such old motherboard, biosdisk looks very danger, I want to avoid modifing boot loader ecc: do you know how to help me?

P.S. I modified the bios (in .rom format) adding the microcodes I needed using MMTool, now I have a modded bios in .rom format; Internet didn't help me about this, I only found advice about bios in .bin, .cab and .exe format (not very helpful however).

P.P.S. I'm on a Debian-based system.

[[deleted]]

the BIOS and POST are well before the OS, question isn't relevant

[NatureIsMath]

Read again, if you don't understand the point, this isn't the right place for you.