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WINDOWS 8 Boot from DVD/CD or USB Flash

Discussion in 'Windows 8' started by Macboatmaster, Feb 6, 2013.

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  1. Macboatmaster

    Macboatmaster Trusted Advisor Thread Starter

    Jan 14, 2010
    BOOT a Windows 8 computer, on which the firmware is UEFI and not the traditional BIOS, from a DVD/CD or USB Flash drive.

    1. My reason for posting this topic is to clarify, what may be a misunderstanding by some people, regarding the procedure for booting a computer with UEFI and therefore GPT partition system. Although this existed before Windows 8, it is inherent on all computers, sold with Windows 8 pre-installed.

    2. UEFI was NOT contrary to the belief of some people introduced by Microsoft. It was INTEL who designed the UEFI (BIOS) system. I have even seen it posted, that UEFI and Secure boot are a devious invention of Microsoft, to make it difficult for people who decide they do not like Windows 8 to return to Windows 7.

    3. UEFI cannot boot from a device on which the file system is NTFS. It can read NTFS file systems but must boot from a FAT32 file.

    4. The GPT partitioning of the hard drive, creates a small partition formatted FAT32 and it is from there, that Windows boots. Whilst the actual partition on which Windows is installed is the NTFS file system.
    When the computer is powered on, it is UEFI that first handles the POST procedure. It then hands control to
    Windows Boot Manager which contained in the FAT32 partition.
    (please note - this is a simplified basic explanation)

    5. Should it be necessary to boot from Flash pen drive, that device must contain the necessary file in FAT32 format for the UEFI to allow the boot.

    6. In all systems there is a facility to disable UEFI by enabling Legacy boot. This in effect has now returned the system to BIOS. In order to enable that procedure Secure boot must be disabled first. Secure boot is found on ALL computers sold with Windows 8 pre-installed AND bearing the Microsoft certified for Windows certificate. This was a decision by Microsoft but ONLY this and not the false belief that they invented UEFI

    7. If legacy boot is enabled then the computer MAY boot, as was the case in BIOS from devices, in the traditional manner, for instance the common use of MEMTEST or disk health check utilities.
    However it is not quite as simple as that - Memtest for instance will not run correctly, even if legacy boot is enabled.

    8. In my opinion and I have spent hours and hours studying the issues and prepared a couple of articles on these matters - the changing of settings in the UEFI user interface to enable legacy boot or use the CSM facility (not found on all computers) to boot the computer from a DVD/CD or flash pen is for the average user UNNECESSARY and INADVISABLE.
    If you get it wrong, not only will the computer NOT boot from the device, it may well not load Windows, even when you cancel the option to boot from the other device.

    9. It is NOT necessary to enable legacy boot. Depending on what utility/program you are attempting to boot from, what is necessary is that the flash pen is formatted FAT32 before the files are added and those files must contain the boot file. As the UEFI after POST will hand control to the boot file on the USB.

    10. As I mentioned above, disabling secure boot is safe. However then enabling legacy boot and running programs, test utilities from legacy boot is NOT, for the average user you may well encounter serious problems.

    11. Boots from DVD/CD are a slightly different issue as a optical disc is not of course formatted FAT 32 or NTFS.
    It simply must contain the correct boot file.
    This explains the problem and although it applies to the installation of Windows the principle applies to booting from a disc for other purposes.

    12. Some people have attempted to dual boot Ubuntu or other Linux based OS from legacy boot. It is not necessary the NEW Ubuntu 64 bit version includes the boot loader for the UEFI system and all that is necessary is to disable secure boot.
    If you attempt to install Ubuntu in legacy boot you MAY never recover to the Windows boot.

    13. Finally I make no apologies for repeating the warning - for the average user
    DO NOT enable legacy boot, in an attempt to boot from a device - to solve problems in Windows 8.

    14. UEFI GPT Partitions - PLEASE NOTE the FAT32 partition that enables the boot

    POST - Power on Self Test
    BIOS - Basic Input Output System
    UEFI - Unified Extensible Firmware Interface
    GPT - Globally Unique Identifier Partitioning Table

    6 Feb. 2013
  2. TerryNet

    TerryNet Terry Moderator

    Mar 23, 2005
    Thank you, Macboatmaster! :) This is very timely for me, as I intend to very soon start experimenting with booting as you describe.

    I first wanted to see what one of these new fangled GPT disks look like. In case others do also, attached are two "pictures" of the disk on a new laptop. Lenovo says there is also a hidden ("Recovery") partition.

    Attached Files:

  3. Macboatmaster

    Macboatmaster Trusted Advisor Thread Starter

    Jan 14, 2010

    Indeed I have just added to my post - in an attempt to further illustrate the FAT partition - although it is of course shown on your screenshots

    This shows perfectly I think why UEFI will not boot from flash drives in the way we are all familiar with on BIOS. They must be FAT32 and contain the required boot file.
    When people start disabling other than secure boot and then enabling legacy boot and then having the computer boot to whatever the bootable media is - it frequently proves to be a course to disaster.

    I am sure you know but I THINK
    The 1000MB is the Windows Recovery Environment tools for the laptop to boot to those
    The 20GB is the Lenova recovery partition to factory condition
    I think D drive is simply extra storage - I have read there are a few drivers stored there
    I do not know what the 1000MB OEM partition is - some have suggested it is used for the activation of purchase of bundled trial software
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