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    Help with vBIOS overclocking disabled by CSM and Secure Boot

    Discussion in 'Asus' started by tocirahl, Aug 4, 2015.

  1. tocirahl

    tocirahl Notebook Consultant

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    I need some help understanding the interaction between CSM, Secure Boot and a custom vBIOS.

    I have an ASUS N550JK laptop with a NVIDIA GTX 850M graphics card. NVIDIA has the card locked down so that you only overclock up to about ~1200 MHz on the core, so I modded the vBIOS to overclock the card further. Now the vBIOS lives as a module in the mainboard BIOS. The overclock works fine when I boot up with CSM (Compatibility Support Module) Enabled, and Secure Boot off, but will not work with CSM Disabled, or Secure Boot on, which will boot with stock clocks. This happens on both Windows 10 and Windows 8.1 (both UEFI installs).

    Does anyone know why this is happening or if there's a way to allow me perform a secure boot, but still retain my vBIOS overclock?

    Here's a link to my BIOS: http://1drv.ms/1ML8e8i

    TL;DR: Disabling CSM disables my vBIOS overclock. Why is this?
     
    Last edited: Aug 4, 2015
    tocirahl, Aug 4, 2015
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  2. Meaker@Sager

    Meaker@Sager Company Representative

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    Does your bios maybe have a legacy half and UEFI half?
     
    Meaker@Sager, Aug 5, 2015
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  3. tocirahl

    tocirahl Notebook Consultant

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    Yes. I have figured out this problem. Turns out the vBIOS I was editing was the Option Rom vBIOS that is loaded in compatibility mode. In EFI boot, there's a separate vBIOS stored in the BIOS image that gets loaded. I simply overclocked that one to the same clocks, and now everything works as expected. For anyone with the same issue, the exact module that contains the second vBIOS is C5D7EAAD-B218-482C-A909-E3B8CDB00E94, which you can find and extract using MMTool.
     
    tocirahl, Aug 5, 2015
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  4. Meaker@Sager

    Meaker@Sager Company Representative

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    Interesting that they did do that rather than combining it into one file.
     
    Meaker@Sager, Aug 6, 2015
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