UEFI or Windows Boot Manager?


  1. Posts : 87
    Windows 10 Pro 64-bit
       #1

    UEFI or Windows Boot Manager?


    I apologize in advance if I sound dense, but I'm seeing something in the BIOS that doesn't make sense to me.

    I have three different SSDs at this time, one each for 7, 10 upgrade, and 10 clean (the last is a slow work in progress). All of the SSDs are GPT* and SATA is set to AHCI in the BIOS.

    If I switch from one SSD to another and look at the BIOS before booting, UEFI: Drive 0 (brand/model) appears as the boot option from the SSD.

    If I reboot and look at the BIOS, the UEFI option is replaced with Windows Boot Manager.

    Is this normal? If not, what am I missing?

    *I included the asterisk because I initially installed 7 as MBR, not knowing the difference. I was able to convert it to GPT using a separate SSD and a process posted at Macrium's website. This shouldn't make any difference in the BIOS, but I figured I'd mention it anyway.
    Last edited by cpmusic; 30 Nov 2015 at 16:44.
      My Computer


  2. Posts : 5,169
    64bit Win 10 Pro ver 21H2
       #2

    It's normal, the same happens on my system.

    The following explanation was found on Wikipedia:
    Unlike BIOS, UEFI does not rely on a boot sector, defining instead a boot manager as part of the UEFI specification. When a computer is powered on, the boot manager checks the boot configuration and, based on its settings, loads and executes the specified operating system loader or operating system kernel. The boot configuration is a set of global-scope variables stored in NVRAM, including the boot variables that indicate the paths to operating system loaders or kernels, which as a component class of UEFI applications are stored as files on the firmware-accessible EFI System partition (ESP).
      My Computers


  3. Posts : 5,478
    2004
       #3

    cpmusic said:
    If I reboot and look at the BIOS, the UEFI option is replaced with Windows Boot Manager.

    Is this normal? If not, what am I missing?
    What does your bcdedit say in the path here? Does it change?
    Code:
    Microsoft Windows [Version 10.0.10586]
    (c) 2015 Microsoft Corporation. All rights reserved.
    
    C:\Windows\system32>bcdedit
    
    Windows Boot Manager
    --------------------
    identifier              {bootmgr}
    device                  partition=\Device\HarddiskVolume2
    path                    \EFI\refind\refind_x64.efi
    description             Windows Boot Manager
    locale                  en-US
    inherit                 {globalsettings}
    default                 {current}
    resumeobject            {9c34aeea-9152-11e5-9c76-00155d013517}
    displayorder            {current}
                            {2bd3fb00-6091-11e5-86c4-c3a22c898ce3}
                            {2bd3fafe-6091-11e5-86c4-c3a22c898ce3}
                            {2bd3faf0-6091-11e5-86c4-c3a22c898ce3}
                            {2bd3fb07-6091-11e5-86c4-c3a22c898ce3}
    toolsdisplayorder       {memdiag}
    timeout                 3
    Windows has a habit of resetting mine to \EFI\Microsoft\Boot\bootmgfw.efi and I have to reset it with bcdedit /set {bootmgr} path \EFI\refind\refind_x64.efi as I don't want the Windows one.

    I've not narrowed down when it does this exactly. Upgrading or clean installing Windows definitely does. So does dual-booting and doing something that messes with the firmware settings (turning on bitlocker for example, some bootrec commands)..

    So to answer your question, yes it is normalish at least for me.
      My Computer


  4. Posts : 87
    Windows 10 Pro 64-bit
    Thread Starter
       #4

    Thanks, folks. I appreciate the feedback. I still have trouble wrapping my mind around some of these things.

    lx07, this is what I get from bdcedit (this is on the upgrade installation). There's more under Windows Boot Loader, but it looked like this is all you were asking about. There are differences in the path, displayorder and timeout, but I don't know how much is related to upgrade vs clean installation, or whether any of it matters.

    Code:
    Microsoft Windows [Version 10.0.10240](c) 2015 Microsoft Corporation. All rights reserved.
    
    
    C:\WINDOWS\system32>bcdedit
    
    
    Windows Boot Manager
    --------------------
    identifier              {bootmgr}
    device                  partition=\Device\HarddiskVolume2
    path                    \EFI\Microsoft\Boot\bootmgfw.efi
    description             Windows Boot Manager
    locale                  en-US
    inherit                 {globalsettings}
    default                 {current}
    resumeobject            {c893dd65-8b0e-11e5-9759-902b343aa354}
    displayorder            {current}
    toolsdisplayorder       {memdiag}
    timeout                 30
      My Computer


  5. Posts : 4,131
    Windows 3.1 to Windows 11
       #5

    there are several ways to run multi-boot systems...

    You appear to have 3 ssd's each containing a separate OS..

    You can setup each SSD with its own EFI/Boot partition - but the switch between OS's you would have to keep changing Boot Order priority in the BIOS everytime...

    Or you can setup ONE EFI/Boot partition on the primary drive - and when booted you will be given the option (via Bootmanager)
    to boot the OS contained on any of the 3 ssd's

    How are you managing the multi-boot option ??

    PS - all systems boot via a Boot Manager
    No matter MBR or UEFI

    What your Boot manager is telling me - Is that it does not display the option to select which OS to Boot
      My Computer


  6. Posts : 4,131
    Windows 3.1 to Windows 11
       #6

    But what you stated in your first post is correct..
    When you change Boot drive priority in the bios - it will state the Drive number and description
    Once you boot that drive the first time - it finds the Bootmanager for that drive - and that Bootmanager is now displayed in the bios
      My Computer


  7. Posts : 87
    Windows 10 Pro 64-bit
    Thread Starter
       #7

    Thanks, Kyhi. I have been thinking of running a dual boot with 7 and 10, but I'm not sure how much I'll need or use 7 once I get everything straightened out. Right now I'm just moving the cables from one disk to another, and I'll probably keep the upgrade only until I get the clean install up to date with my software (it's currently in Procrastination Mode).
      My Computer


 

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