[Solved] UEFI Windows install from Legacy BIOS booted USB

Discussion in 'BIOS Mods' started by Xat, Aug 2, 2016.

  1. Xat

    Xat MDL Novice

    Dec 3, 2014
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    Is it possible to force Windows to install in UEFI boot mode when installing it from a USB Key booted in Legacy BIOS mode?
     
  2. jukanmanya

    jukanmanya MDL Novice

    Apr 28, 2013
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    Not as far as I know, you have to boot in UEFI mode to be able to do UEFI install.

    I'd like to see an answer to this too but doubt it's possible.
     
  3. sebus

    sebus MDL Guru

    Jul 23, 2008
    5,782
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    Of course it is. Just do NOT run setup, but dism /apply with GPT created structure

    diskpart /s partitiondisk_uefi.txt

    get the commands used from here

    Dism /apply-image /imagefile:USB_DRIVE_LETTER\sources\install.wim /index:1 /ApplyDir:W:\

    W:\Windows\System32\bcdboot w:\Windows /s S: /l en-US /f ALL

    On reboot one has to change boot option to UEFI
     
  4. Flipp3r

    Flipp3r MDL Expert

    Feb 11, 2009
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    Sebus is correct. If your USB key is a copy of the Windows ISO, you can press SHIFT+F10 to open a command prompt & then enter his commands.
    Or simply boot your USB key in UEFI mode...
     
  5. Xat

    Xat MDL Novice

    Dec 3, 2014
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    Thank you sebus!
    I have also found a tool called murphy78's DiskPart and Apply script coded by murphy78 that should do what I was looking for