BIOS settings for W7

Discussion in 'Windows 7' started by puffyduff, Apr 19, 2018.

  1. puffyduff

    puffyduff MDL Member

    Sep 22, 2016
    #1 puffyduff, Apr 19, 2018
    Last edited: Apr 19, 2018
    New BIOS options for new boards are kinda complicated to me.

    Obviously CSM has to be enabled. 2 additional settings pop when it's enabled:

    Storage boot options control:
    - Legacy (I've read if this was chosen, AHCI wouldn't work?)
    - UEFI (UEFI in CSM? Whaat?)

    Other PCI Device

    - Legacy
    - UEFI

    Q1: What the hell is going on here? Isn't CSM legacy itself? Can I have CSM on and still have UEFI enabled for these?

    Also, If CSM is enabled then there will be 2 boot options for THE SAME drive, like:

    - DVD-RW
    - UEFI: DVD-RW

    Q2: You must boot from NON-UEFI option according to Daz Loader's Readme. Is that right?

    The loader doesn't work when the systems using GPT. The workaround is to pre-format your hard drive so that it uses MBR instead.
    From your BIOS select to boot the Windows DVD without UEFI, press and hold SHIFT and then press F10 and then enter this:
    list disk
    select disk 0
    convert mbr
    create partition primary
    select partition 1
    format fs=ntfs quick
    Boot the Windows DVD the same way you did the first time.
  2. urie

    urie Moderator
    Staff Member

    May 21, 2007
    The Compatibility Support Module (CSM) is a component of the UEFI firmware that provides legacy BIOS compatibility by emulating a BIOS environment, allowing legacy operating systems and some option ROMs that do not support UEFI to still be used.

    Suffice it to say that if your PC is fairly new and came with Windows pre-installed, CSM would've been disabled by default. You don't need to enable it. It's only needed if you must install an older OS that doesn't support UEFI.
  3. GodHand

    GodHand MDL Addicted

    Jul 15, 2016
    1) CSM is Legacy emulation, whereas enabling Legacy mode is just that, switching the BIOS' UEFI firmware to accommodate any physical device that supports legacy operating systems. CSM, or rather, Legacy emulation, does not switch a BIOS' UEFI firmware to accommodate said physical devices, hence why CSM does not support the range of devices that pure Legacy mode does.

    2) There is a lot of misinformation on how one can go about installing Windows 7 in a UEFI environment. Furthermore, you do not need to boot from a non-UEFI device. You can easily create a UEFI bootable USB/ISO and install Windows 7 with it. However, to install Windows 7 in pure UEFI mode - that is, without CSM or the like - you need to apply the image directly to the drive and either A) use BCDBoot to apply the proper boot-up configuration files to the System drive, utilizing the exact System.Object (the WIM applied to the drive) for its configuration; or B) Creating an object to load custom BCD settings by getting the default OS loader and Element ID. Neither is difficult to do so long as you use the proper constants.

    From one of my WIM functions:

    $BOOTMGR_ID                          = "{9DEA862C-5CDD-4E70-ACC1-F32B344D4795}"
    $DEFAULT_TYPE                       = 0x23000003
    $APPLICATION_DEVICE_TYPE  = 0x11000001
    $OS_DEVICE_TYPE                   = 0x21000001
    You'd probably just be better off creating a UEFI ISO/USB and installing Win7 using UEFI + CSM. No harm there.
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  4. catsmoke

    catsmoke MDL Novice

    Feb 9, 2018
    You recommend installing Windows 7 by using "UEFI + CSM" and then say "No harm there" but this confuses me.

    If UEFI is superior to CSM, then CSM must have some inferior factor. By using a UEFI-only approach, one is sure to be free from CSM's inferior factor. But the approach UEFI + CSM potentially includes CSM's inferior factor, and therefore by using this UEFI + CSM approach, one is potentially sacrificing whatever superiority that one had hoped to achieve, by solely using UEFI. So the assessment "No harm there" seems incorrect. The harm is the inclusion of CSM's inferior factor (whatever it may specifically be).

    Perhaps one can use the UEFI + CSM approach, and have faith that CSM will actually play no role, and that CSM's inferior factor will not cancel out the advantage provided by UEFI, but that would be entering darkness.

    I have little knowledge regarding these things, so please pardon my criticism, but to those who seek to escape CSM's inferiority, the casual advice to combine its usage with that of UEFI seems problematic.
  5. Carlos Detweiller

    Carlos Detweiller MDL Spinning Tortoise

    Dec 21, 2012
    Windows 7 needs CSM, it cannot boot UEFI natively but still relies on BIOS INT10 emulation.
    The CSM setting in the firmware SETUP is usually irrelevant, the legacy INT10 features will be applied to Windows 7 if required.
  6. atgpud2003

    atgpud2003 MDL Senior Member

    Apr 30, 2015
    Recommended to disable UEFI+CSM.. No need for Windows 7, just use Standard ACHI that all..