These kind of BIOS modding shenannigans is why I got interesed in Coreboot, so that enhancing a Firmware capabilities becomes possible without touching propietary tools/code.
Other similar mods included adding NVMe Boot capabilities to older Firmwares that didn't supported them so that you could boot from modern NVMe drives if you used some kind of adapter (As none of those Motherboards have M.2 Slots, but you can use them with a PCIe-to-M.2 adapter card). Also adding required stuff to get certain CPUs booting in Motherboard that were never officially supported (Depending on generation, could be as simple as adding new CPU Microcode).
These days you might be able to just point an AI at the original BIOS and tell it what you need done, instead of attempting to install a complete rewrite like Coreboot (which comes with its own limitations, the biggest one being that only a rather small subset of mobos are actually supported.)
Regarding Coreboot, it is far worse than that. They literally do not care anymore; focus is not on corebooting all the boards, but on serving some sort of commercial "customer".
e.g. they do seldom if ever take patches for adding support or fixing issues in older boards. They just sit there ignored.
A fork or entire new project with different focus is sorely needed.
There is also the Libreboot which may be of your interest. What I see is that there is a lot of development on Coreboot but it is indeed mostly driven by companies working on their latest platforms. There are not many contributors working on older platforms. Though in my experience the response to patches is relatively quick.
I had the exact opposite impression, there are a lot of user contributions working on old platforms, and even specific platform communities. For example, you have 15h.org which is a community dedicated to AMD Bulldozer / Piledriver generation, and they managed to fix a few things that were left broken in Coreboot. I also saw an influx of users working in Sandy Bridge / Ivy Bridge / Haswell era Intel platforms with an occasional Skylake. The problem is, precisely, that most of the user contributions are for old platforms that nobody that does NOT currently owns those will want to touch if you're purchasing new. I would have been very enthusiastic about that work if it was done about 10 years ago or so, nowadays they seem to be hobby projects that don't advance anything forward.
There do exists individual users that work on newer stuff, after the MSI Z690-A / Z790-P there were 2 people that did ports for H610 since at that point the platform was supported and they only had to port the Motherboard. However, they are rather rare, since the kind of user that Coreboot seems to attract are from the privacy and security anti-ME/PSP crowd that don't even want to use newer platforms, which is the exact opposite of my view.
A lot of the work companies does may be just for their internal systems or reference platform and these may not get to the hands of end users, ever. I still recall Phoronix articles covering Coreboot releases always taking a jab at the new supported Motherboards until the MSI Z690-A DDR4 port from 2022.
zir_blazer · · focus · HN ↗
Other similar mods included adding NVMe Boot capabilities to older Firmwares that didn't supported them so that you could boot from modern NVMe drives if you used some kind of adapter (As none of those Motherboards have M.2 Slots, but you can use them with a PCIe-to-M.2 adapter card). Also adding required stuff to get certain CPUs booting in Motherboard that were never officially supported (Depending on generation, could be as simple as adding new CPU Microcode).
userbinator · · focus · HN ↗
snvzz · · focus · HN ↗
e.g. they do seldom if ever take patches for adding support or fixing issues in older boards. They just sit there ignored.
A fork or entire new project with different focus is sorely needed.
trashb · · focus · HN ↗
zir_blazer · · focus · HN ↗
There do exists individual users that work on newer stuff, after the MSI Z690-A / Z790-P there were 2 people that did ports for H610 since at that point the platform was supported and they only had to port the Motherboard. However, they are rather rare, since the kind of user that Coreboot seems to attract are from the privacy and security anti-ME/PSP crowd that don't even want to use newer platforms, which is the exact opposite of my view.
A lot of the work companies does may be just for their internal systems or reference platform and these may not get to the hands of end users, ever. I still recall Phoronix articles covering Coreboot releases always taking a jab at the new supported Motherboards until the MSI Z690-A DDR4 port from 2022.