Asus X75VC - Force bios update

Discussion in 'BIOS Mods' started by mr_chaela, Jun 26, 2014.

  1. mr_chaela

    mr_chaela MDL Novice

    Aug 8, 2009
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    Just bought an Asus X75VC-TY103H notebook which came preloaded with Windows 8. I need to put win 7 on it.

    It has bios version 202 on which hides the ability to disable Secure Boot. The latest bios on the Asus site is 201 which I believe allows for secure boot to be disabled. How can I force this bios downgrade?

    TIA
     
  2. mr_chaela

    mr_chaela MDL Novice

    Aug 8, 2009
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    Well I finally got to force a bios downgrade, using Winflash /nodate from command prompt, however the 201 bios still wont allow me to disable secure boot, everything to do with UEFI is hidden.

    Anybody got an ideas on this?
     
  3. nexus76

    nexus76 MDL Addicted

    Jan 25, 2009
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    #3 nexus76, Jun 27, 2014
    Last edited: Jun 27, 2014
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  4. mr_chaela

    mr_chaela MDL Novice

    Aug 8, 2009
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    Hi nexus76

    many thanks for the help, will mod bios as you suggest and report back the result.
     
  5. mr_chaela

    mr_chaela MDL Novice

    Aug 8, 2009
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    #5 mr_chaela, Jun 27, 2014
    Last edited: Jun 27, 2014
    (OP)
    Modified bios file as suggested with AMIBCP ver. 4.55.0070 but get error with winflash 'The BIOS file size is not valid'

    Just spent an hour or so searching for a solution but getting nowhere.
    Is the a solution to this?

    tia

    edit.
    Tried using AMIBCP ver. 4.53 and get error with winflash 'Invalid BIOS file'
     
  6. nexus76

    nexus76 MDL Addicted

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  7. mr_chaela

    mr_chaela MDL Novice

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    #7 mr_chaela, Jun 28, 2014
    Last edited: Jun 28, 2014
    (OP)
    No luck unfortunately.

    From the UEFI Tool:
    The original bios shows a capsule with bios image
    If I mod with AMIBCP4.55.0070 the bios just shows an image (00600800bytes)
    If I mod with AMIBCP4.53 the bios shows a capsule with bios image (same sizes as original)

    It seems that AMIBCP4.53 saves in the right format but corrupts the file
    and AMIBCP4.55.0070 saves in the wrong format

    I don't know what to do next.
    Thanks again for help

    ps. Is the EUFITool screen cap in your last post the actual X75VCAS201 file
     
  8. nexus76

    nexus76 MDL Addicted

    Jan 25, 2009
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    secure capsule check


    the problem is now to get rid off the secure capsule check. otherwise you won't be able to flash a modified bios.
    please try to dump nvdata with sce from an admin cmd:

    SCEWIN_64 /o /s nvram.txt /h Hii.db /v /q

    and upload the nvram.txt file! thanks
     
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  9. mr_chaela

    mr_chaela MDL Novice

    Aug 8, 2009
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    Hi nexus76
    Sorry for delay, but having troubles getting the nvram.txt file. Using AMISCE Utility Ver 2.02.1036 in cmd (run as admin) I get the following:-
    ERROR:4 - Retreiving Hii Database
    ERROR:4 - Dumping Hii Database to File

    I tried updating bios (modded with AMIBCP4.53) using Easy Flash in Bios Setup and it only complained that bios file was too old, so maybe the answer would be to reset the bios build date. I looked at the bios file with HxD and found 3 instances of the date (searched for 2013), changed all three to 2014, but don't know how to reset the checksums, EUFITool messages show the details but I'm not sure what to change in HxD or whether this would work.

    Thanks again for your help and time,
     
  10. nexus76

    nexus76 MDL Addicted

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    #10 nexus76, Jul 2, 2014
    Last edited: Jul 2, 2014
    mr_chaela,

    did you try to use afudos for flash?
    I see in PCH-IO Configuration that BIOS Lock is set to Disabled by default,
    so you should probably be able to flash ROM files without capsule.
    Another way was flashrom for dos or linux.

    Even the bios recovery mode can be handsome in such a case.

    Regarding bios date: it means asus has locked the downgrade option, you won't be able to flash with ezflash,
    it will accept only RSA signed rom files.
     
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