Well, with my usual "Do something about the BIOS" behaviator, now I come for another round for something that have high chances of being yet another unsucessful attempt.

First of all, you could read some backstory about what I am attemping to archieve in these three Threads:

http://board.flatassembler.net/topic.php?t=6632
http://www.xtremesystems.org/forums/showthread.php?t=87070
http://www.xtremesystems.org/forums/showthread.php?t=247897

Basically, from a standpoint of a Hardware enthusiast more than an Assembler programmer (Something that I am not, but I like to keep in touch with FASM community), many Motherboards manufacturers reduces BIOS functionality in tons of models possibily to justify having to look for a more expensive Motherboard with a more enthusiast friendly and flexible BIOS. But there is nothing holding back these models for not having these options.
While some may argue than overclocking is bad and whatever, most mainstream and even budget Motherboards supports it from two or three generations ago. What they aren't friendly with is undervolting, so you can seek the lowest possible Voltage in components (Mainly Processor) that they function fully stable at and then archieve lower consumption with no drawbacks.

I would like to know if besides being Assembler programmers, someone else shares a Hardware enthusiast side, attemped to mix the two sides and did something to bash these imposed artificial limitations by modding the BIOS to introduce options that should be available, but aren't, or a wider range of options of those currently available. I know that it is possible because from time to time some custom BIOSes surfaces for specific Motherboards, but basically the people that do it is for the models that they can test with.
While it would be risky if I provided testing of any custom BIOS for my Motherboard for money reasons (I can't replace it if I break it), I would like to know if anyone here ever tried anything related to this, how hard it was, and the results of messing with the BIOS.

I think the reason that options are limited is not to force people to buy a more expensive version, but instead to stop people fucking up their system with bad settings. You might be surprised how many people will play with the settings without knowing what they are doing.

But why you would provide a wide range of overvolting options and not the other way around, that is even safer than doing that?

http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/26327-asus-m4a785td-v-evo-m4a785td-m-evo-am3-motherboards-review-11.html

The fun thing is that it is my very own Motherboard, yet in my BIOS the Voltage range doesn't include options below nominal specifications, just to go beyond them. I suppose than it is because they are using another version (0410, I had 0602, then upgraded to 0604), but that is pretty much what I wanted.

Not really. Under-voltage produces errors and unreliable operation. Whereas, over-voltage only produces heat. Since all the later CPUs now have automatic down-clocking when the chip gets too hot, it is almost impossible to kill a CPU with higher voltages (voltages within reasonable limits of course).

Overvolting increases heat and power consumption for absolutely no benefict once you have reached 100% stability for 24/7 operation, besides that at some point you also need better cooling if you're overvolting for archieve stability on higher than nominal Frequencies. This also involves risk of damaging components (Usually not the Processor but the Motherboard, the VRMs don't have advanced protections like the Processor got if you are forcing them too much). Indeed that even when overclocking, if you are doing it in a rational and non extreme fashion, you shouldn't blow anything, but power consumption rises exponentially.
Undervolting indeed makes your system inestable beyond that minimum requiered Voltage to archieve stable operation at a target Frequency. Actually, when you are overclocking you also have the same issue but the other way around, when you have to raise the Voltage to make the Processor stable at a determinated Frequency. However, there is absolutely no risk of damaging forcing components when undervolting (Actually you are relaxing them).
Remember than these days while for many computing power is never enough and always wants more (What usually leads people to overclock), for some people the machines are fast enough already and as enthusiasts, they want to override automatic controls and set these themselves (Reason why I don't want to use Cool'n Quiet).
For example, my Athlon II X4 620 nominal specifications are 2.6 GHz @1.325V for the Processor Cores and 2 GHz @ 1.175V for the integrated Northbridge. Using K10stat I can manually set it within Windows to 1 GHz @ 0.8V and 1.2 GHz @ 0.85V, most of the day I don't need anything more than that. Or I could simply run it at 2.6 GHz but could give it a try to seek the lowest possible Voltage that it may run stable at, saving on power consumption and heat (No need for 1.325V when they seem to be stable at that Frequency at 1.15V or so).

The point is that while I can modify the Processor and Northbridge Multipliers within BIOS to make them boot at 1 GHz and 1.2 GHz respectively, I don't have Voltage controls to undervolt them to the value that I found that it is fully stable at, so I have to open K10stat and lower it everytime that I reset. Besides, with such a low power consumption I could simply run it without the Fan, but it would be several times safer if the BIOS booted at low Voltages instead of nominal ones, in case that anyone resets my machine.

The point is, undervolting is less risky, yet still less supported. And if we're all about green power, saving the planet, and all that trash, I don't see any reason about why there are Motherboards providing full Voltage ranges to blow up components or having tons of power consumption, and at the same time, they are pretty restricting with the enthusiast that could use these additional settings to save power at the same performance, or lower both performance and power consumption to ridicolous levels if they don't need anything more than that.

Perhaps you can consider writing a small pre-boot utility to adjust the settings to your liking. Or, alternatively, write a small Windows utility to make the adjustments and put it in your "run" registry key. Going the BIOS method can introduce its own dangers.

Well, K10stat supports command line parameters, so I could use it at Windows boot without needing to program anything (That I don't know how to do, if at all. My programming career has been a frustrated and fruitless one). However, that is not what I want. The BIOS method is the most practical one, if mine supported it, that is.

What I specifically want to know, is if anyone ever did BIOS modding, not just for this reason, but for any other. Messing with the BIOS file via reverse engineering, modifying it, reflashing it, and not bricking the Motherboard, is indeed a serious accomplishment for an Assembler programmer. In my case, I would want to do it for adding a wider range of values for the actually available options. However, I don't have the knowledge to do so nor I would want to take the risk, but I want to know if anyone else here did.
Besides, I don't know why you seem to be looking for a workaround around my personal dilema with BIOSes instead of just directly tackling at it. Seems that for you my idea simply doesn't make sense, though for me it does and a lot.

It wasn't clear to me what you were wanting. I thought you just wanted to reduce your power consumption.

Anyhow, as for modifying the BIOS code, I used to do it some time back when BIOSes were still on plug in EPROMs. I did it to make embedded systems for industrial control tasks. But for modern mobos, I would recommend one with a dual BIOS option. That way, if you screw up your code, you can always go back to the original and try again.

http://www.bios-mods.com/forum/

The response to all my questions Gonna give a try looking at that place.

A more advanced BIOS modding forum can be found at http://www.rebelshavenforum.com/sis-bin/ultimatebb.cgi?ubb=forum;f=52. It's not for the faint heart . As usual, there are threads which may already answer your question(s).

Alternatively, you could use a virtual machine. VMware uses a Phoenix BIOS. Just an idea, idk.

Have any of you tried messing with a VM's BIOS, or is there some reason why it wouldn't work?