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  1.    04 Feb 2016 #11
    Join Date : Oct 2015
    Posts : 2,112
    Windows 10 Pro X64

    Hi,

    What I can't understand is that with CSM off and Secure Boot on there are "NO" device entries in UEFI boot list other than "Windows Boot Manager"!
    That's to be expected. Imagine the following situation : two HDs each containing a Window 10 install for example and their respective SATA ports enabled.
    These two should show in the bootable device list in bios with csm off and secure boot enabled.

    CSM is a computability mode that allows you to boot from older non UEFI compliant hardware, MBR disks and so forth.
    Note also that in order to run CSM, secure boot needs to be disabled. Most BOIS/UEFI require you to turn off Secure Boot first in order to access CSM mode.

    Cheers,
      My ComputersSystem Spec
  2.    05 Feb 2016 #12
    Join Date : Feb 2016
    Posts : 10
    Windows 10 Pro
    Thread Starter

    Quote Originally Posted by alphanumeric View Post
    That's normal, as far as I know. That's all I see on my laptop, Windows Boot manager. With no other bootable devices plugged in. My second SSD isn't bootable and won't show up in that list. If I plug my bootable thumb drive in its listed though. It shows up as boot option 2.
    Ok, so only Bootable drives will be allowed in the Boot list. I suppose my N1-Samsung SSD 950 PRO 256G drive, with W10 on it, isn't on it's own bootable but is through Windows Boot Manager. The SSD doesn't show in the Sata list either as it uses the M2 slot in the motherboard. I tried my W10 install USB again and indeed it can come up as UEFI: bootable. Where do you get to learn this stuff other than here?
    Thanks guys for your comments.
      My ComputerSystem Spec
  3.    06 Feb 2016 #13
    Join Date : Jun 2015
    UK
    Posts : 2,162
    Windows 10 Home x64 (Laptop), Windows 10 Pro x64 (Desktop)

    I have CSM off, UEFI boot always and secure boot set on both of my PCs. I only ever see the Windows Boot Manager unless I select boot override and insert a UEFI bootable USB flash drive or DVD. I then see the UEFI prefix for these devices and can boot from them.
      My ComputersSystem Spec
  4.    06 Feb 2016 #14
    Join Date : Dec 2013
    Sydney, Nova Scotia, Canada
    Posts : 10,603
    Windows 10 IoT

    Quote Originally Posted by Philip1 View Post
    Ok, so only Bootable drives will be allowed in the Boot list. I suppose my N1-Samsung SSD 950 PRO 256G drive, with W10 on it, isn't on it's own bootable but is through Windows Boot Manager. The SSD doesn't show in the Sata list either as it uses the M2 slot in the motherboard. I tried my W10 install USB again and indeed it can come up as UEFI: bootable. Where do you get to learn this stuff other than here?
    Thanks guys for your comments.
    The "Windows Boot Manager" notation is I believe a UEFI thing. All I see on my desktop PC that is legacy BIOS is the drive ID. On my laptop its the drive ID with Windows Boot Manager in front of it. Same deal with the UEFI notation in front of your bootable thumb drive entry. You'll only see that on a UEFI PC. It's just extra info, as far as I know. I'm sure somebody will correct me if I'm wrong.
      My ComputerSystem Spec
  5.    06 Feb 2016 #15
    Join Date : Oct 2015
    Posts : 2,112
    Windows 10 Pro X64

    Hi,

    Actually you only see these extra tags in front of bootable device when bios is running in compatibility mode (CSM).

    Boot manager is Bios managed, UEFI is obviously UEFI managed.

    Once you set CSM to disabled the prefixes will disappear and only UEFI bootable device will be visible in the boot menu when called up.

    Cheers,
      My ComputersSystem Spec
  6.    06 Feb 2016 #16
    Join Date : Dec 2013
    Sydney, Nova Scotia, Canada
    Posts : 10,603
    Windows 10 IoT

    I have CSM disabled and still see Windows Boot Manager. Disabled is the default setting.
      My ComputerSystem Spec
  7.    06 Feb 2016 #17
    Join Date : Jun 2015
    UK
    Posts : 2,162
    Windows 10 Home x64 (Laptop), Windows 10 Pro x64 (Desktop)

    Not true. I'm in UEFI only mode and see the UEFI prefix.
      My ComputersSystem Spec
  8.    06 Feb 2016 #18
    Join Date : Dec 2013
    Sydney, Nova Scotia, Canada
    Posts : 10,603
    Windows 10 IoT

    It may depend on the UEFI BIOS that's installed? On my wife's Acer laptop, it never ever shows UEFI in front of my UEFI install thumb drive. I can still install in UEFI mode though. This Acer is also very fussy as to how you create the bootable thumb drive. I had to use diskpart to setup my thumb drive for it to even boot from it at all. My ASUS laptop on the other hand, shows the UEFI description and will install in UEFI mode even if the thumb drive is formatted in NTFS.
      My ComputerSystem Spec
  9.    06 Feb 2016 #19
    Join Date : Oct 2015
    Posts : 2,112
    Windows 10 Pro X64

    Hi,

    It may depend on the UEFI BIOS that's installed?
    Quite likely so. Mine is an OEM AMI bios which was factory set to CSM mode by default.
    Doesn't really matter once you know which is which really.


    Cheers,
      My ComputersSystem Spec
  10.    06 Feb 2016 #20
    Join Date : Dec 2013
    Sydney, Nova Scotia, Canada
    Posts : 10,603
    Windows 10 IoT

    CSM enabled or disabled, doesn't seem to make any notable difference on my laptop? My laptops UEFI BIOS is pretty basic though. It doesn't look any different than any other BIOS I've seen. Other than the UEFI and CSM entries that is.
      My ComputerSystem Spec

 
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