UEFI boot query

Discussion in 'other software & services' started by samy, Oct 12, 2019 at 12:07 PM.

  1. samy

    samy Registered Member

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    I have a new laptop DELL Vostro 5481.
    with my previous PC I was using the Legacy BIOS booting.
    My new laptop has a UEFI Mode.
    I would like to have the option (from time to time) to boot using a CD or USB but I have no idea how to do it.
    On the boot device menu I got:
    UEFI BOOT
    Windows Boot Manager
    OTHER OPTIONS
    Bios Setup
    ---------
    Change Boot Mode Settings

    when I click on "Change Boot Mode Settings" I got
    CHANGE BOOT MODE TO
    1) UEFI Boot Mode, Secure Boot OFF
    2) Legacy External Device Boot Mode, Secure Boot OFF

    Ask for guidance how to do it and what " Secure Mode OFF" means
    Thanks
     
  2. Seer

    Seer Registered Member

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    I'm just assuming it's Windows.
    You won't get any better than this -
    https://docs.microsoft.com/en-us/wi...desktop/boot-to-uefi-mode-or-legacy-bios-mode
    Check your BIOS for an entry that says "Boot order' or something similar. All BIOSes have this feature. It will list all bootable devices and you can change the order as you like.

    EDIT: take a look here as well -
    https://www.thewindowsclub.com/how-to-change-legacy-to-uefi-without-reinstalling-windows-10
     
  3. samy

    samy Registered Member

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    Thanks Seer for your prompt answer.
    I am using Windows 10 (x64)
    the Bios is showing exactly what I mentioned in my thread above. The lonely option that I have is " Windows Boot Manager" i.e. through the HD only.
    Can I change (safely) the boot mode. to 1) UEFI Boot Mode? or to 2) Legacy? (see my previous thread)
     
  4. Seer

    Seer Registered Member

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    Before you switch Legacy to UEFI in BIOS, you have to first convert MBR to GPT using the mbr2gpt command line tool. Otherwise the OS won't boot.
    I will summarize -

    Reboot the PC while holding the Shift key simultaneously. The recovery Environemt will appear after a reboot.
    Go to Troubleshooting->Advanced, find Command Prompt and open it.
    Type

    Code:
    mbr2gpt /validate
    This will only verify if a disk can be converted without performing the actual conversion

    Code:
    mbr2gpt /convert
    This will verify if a disk can be converted AND perform the actual conversion

    When it's finished, reboot and immediately enter BIOS. Now you can switch from Legacy to UEFI.
    Reboot and you should be at your desktop.

    This is all assuming that you hava a single drive in the laptop. If not, there's a

    Code:
    mbr2gpt /disk:<disknumber>
    switch to change the disks. You can see all mbr2gpt switches here.
     
  5. samy

    samy Registered Member

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    Aug 18, 2008
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    Hi Seer
    IMHO what you describe is how to switch Legacy to UEFI in BIOS.
    The Bios in my laptop is already UEFI.
    In a video (youtube) I have been forwarded to, thru the link you mentioned it is said that the UEFI is a secured mode and it is not allowing to boot using an external device unless removing this security status.
    (https://www.youtube.com/watch?v=D7NuwQWYWKw)
    what is the impact on the operating system if I cancel this security status ("Secure Boot OFF")
    I am really lost because I don't know how to use a Macrium Reflect recovery disc for example.
     
    Last edited by a moderator: Oct 12, 2019 at 4:16 PM
  6. pandlouk

    pandlouk Registered Member

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  7. Seer

    Seer Registered Member

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    I see. I misunderstood you.
    The video is not conclusive and I was not aware that changing boot devices can be vendor-specific, and even impossible to enable.
    I must say I'm stumped.
    Better to wait for @Brian K or someone who had some more experience with UEFI on various systems.
    Well, here's Panagiotis.
     
  8. pandlouk

    pandlouk Registered Member

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    Last edited: Oct 12, 2019 at 4:50 PM
  9. Brian K

    Brian K Imaging Specialist

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    Location:
    NSW, Australia
    Great article.
     
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