Requesting help to mod Z390-A Pro bios

Apr 23, 2021
Hello everyone, my apologies for the long post but want to be as detailed and clear as possible,

I have the MSI Z390-A pro motherboard:
and I am currently using the latest BIOS version available on MSI website for my model Z390-A Pro, which is Version 7B98v1D with release date 2021-02-08.

I would like some help with unlocking the following 3 hidden features/settings on my MSI Z390-A Pro motherboard bios:

1. RFI Spread Spectrum Settings

2. PCIE Spread Spectrum setting on/off setting

3. HPET timer on/off setting

I have analyzed the latest bios file ( E7B98IMS.1D0 ) with 3 different UEFI tools/editors, (SCEWIN_64.exe, AMIBCP patched version for z390 boards, and UefiBiosEditor) ,

and can confirm the settings I want to unlock are there in the bios, but hidden from user.

RFI Spread Spectrum setting is enabled by default and at 1.5% value, with 6% being maximum value, I want to change from default 1.5% value to maximum 6% value.

PCIE Spread Spectrum setting is enabled by default, and would like to unlock this to test on/off setting.

HPET timer is enabled by default, although the hpet timer can be forced off via windows, and as far as I understand it is not used on a default windows 10 install,

(unless specifically forced via bcdedit /useplatformclock yes ?)

so the HPET setting is not so important setting for me, mostly interested in the RFI Spread Spectrum setting and the PCIE Spread Spectrum setting,
would still be nice to unlock it for testing purposes.

I have found all 3 settings with the 3 above mentioned tools, here is screenshot examples from AMIBCP:

1. RFI Spread Spectrum Settings in AMIBCP tool

2. PCIE Spread Spectrum Setting in AMIBCP tool

3. HPET Timer Setting in AMIBCP tool

and here is how the 3 settings look when I export the bios file with SCEWIN_64.exe:

1. RFI Spread Spectrum settings exported from SCEWIN_64.exe to textfile

2. PCIE Spread Spectrum setting exported from SCEWIN_64.exe to textfile

3. HPET Timer Setting exported from SCEWIN_64.exe to textfile

My question now is, how complex of a mod would it be to fully unlock these 3 options? to me it seems 2. and 3. should be more or less simple and straightforward
as they are simple on/off settings, but 1. RFI Spread Spectrum settings seem a bit more complex since it is group of settings and kind of a sub-menu?

If it is complex and risky to try and fully unlock this RFI menu, then all I really am interested in is to just unlock the "main" RFI Spread Spectrum setting,
the one where the options are 0.5% , 1% , 1.5% (default enabled in bios) , 2% , 3% , 4%, 5% , 6% (maximum value)

this specific setting has offset "8A0" when exporting bios to textfile via SCEWIN_64.exe , and handle "07E3" when looking at bios file with AMIBCP.
(can see in screenshots above)

if it is too complex to unlock this menu or whole RFI Spread Spectrum settings for some reason, then I would like to just set maximum value 6% and no other changes,
even if this means option will still be hidden in bios.

I was looking at attempting this myself, for example the SCEWIN_64.exe tool has both a import.bat and export.bat , when running export.bat
it will dump current bios to a textfile with name BIOSSettings.txt , and that is how I got the "exported from SCEWIN_64.exe" screenshots above.
now there is also an import.bat, my idea was to just move the * from [03]1.5% to [08]6% , but question is what happens when I then run import.bat with admin priviledges?

if someone is familiar with SCEWIN, can this tool actually flash the bios while windows 10 is running? or will it flash on reboot or similar effect?

if this is not how it works, or bad idea, maybe someone could help me a bit here? can I just edit the bios file with AMIBCP and change the 1.5% setting there to 6% somehow?
again that RFI Spread Spectrum setting is the most important thing I want to test, and also PCIE Spread spectrum setting would be nice to have, HPET timer setting is not so important.

the perfect situation would be to modify the bios file so that all 3 settings are unlocked, and in same file format as original bios file, so that I can just put modded bios on USB
and flash from inside bios like normal bios flash for example,
but if it really works to just flash from windows via SCEWIN tool then I could also try to just put the * at 6% setting and run import.bat?

would greatly appreciate any help here or at least some sharing of general knowledge/information about this process and what best method is to proceed.

Thanks in advance and kind regards,