I really need help figuring out how to mod my BIOS. My motherboard ASUS P8B75-M/CSM doesn’t allow me to go below 60% duty cycle for chassis fans or below 20% for CPU fans. I have a programmer and dumped the BIOS successfully. There’s two chips on the motherboard which one appears to be the BIOS itself and another is Intel ME according to UEFITool, not really sure. I tried extracting AMITSE using UEFITool but it ends there, not sure what to do next.
Use AMIBCP 4.53.0050
are you sure changing the optimal value via AMIBCP works? I figured there’s more to it but I can try and see if it works soon.
This is not possible, we’ve tried MANY ways on several various Asus BIOS for different users. Someone with extreme assembly knowledge needs to teach someone how to do this, it’s not a simple setting or value change in any normal mod BIOS or mod allowed value areas
And be VERY careful about what chip and contents goes into what slot on this board! The contents of each chip and their location are critical, can’t be swapped around.
The non BIOS chip contains FD/ME and other info.
* Edit - The only person I think may be able to help or know how to do this is @ReousI - IF he ever figured out stuff we were working on before
Thank you for the heads up 
I guess an alternative is to solder a resistor in series to turn down the fan speed? I saw somewhere you can put the fan ground wire to +5V on a molex connector though I’m not sure if that’s a good idea…
@BentPins - Yes, that is valid option if you know how and where to do it. Sorry, I have no advice on doing that though, you’ll need to find some exact advice about that, or a guide etc, somewhere before you do anything
I believe ReousI knows how to change the allowed input value, which he had success back when we tried to sort (This and or similar setting) before, but at that time the actual applied value was not being changed, so maybe by now he’s figured out how and where to make the actual value change as well.
I think he was working on a voltage entry, but it’s same kind of thing, you have to change the allowed entry value and then other edit is needed where it actually makes the value apply properly vs the previous limited one.
Hello again, I’m willing to give my BIOS dumps for modding and testing if anyone is interested. As of now I’m using a resistor to lower the speed but I’m not satisfied with this setup. When the PC is under load, the fan speed is capped lower than without the adapters. If it’s still not possible to lower the duty cycle, my only choice is to upgrade the motherboard that have all PWM fan headers (and all other components) which would also mean replacing my 3-pin case fans with PWM fans. Very expensive route though, hopefully It goes well.
Hello again, I’m willing to give my BIOS dumps for modding and testing if anyone is interested. As of now I’m using a resistor to lower the speed but I’m not satisfied with this setup. When the PC is under load, the fan speed is capped lower than without the adapters. If it’s still not possible to lower the duty cycle, my only choice is to upgrade the motherboard that have all PWM fan headers (and all other components) which would also mean replacing my 3-pin case fans with PWM fans. Very expensive route though, hopefully It goes well.
Hi I really need the non bios dump if you could share