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Installed UEFI 8.1 (clean) boot partition & more...

  1. #1

    Installed UEFI 8.1 (clean) boot partition & more...


    The title of this thread was too descriptive to fit within the character allotment...;) Here's what I would have titled it had things not been truncated:

    Installed UEFI 8.1 (clean) boot partition alongside 8.1 Legacy boot installation in the same system!

    Here are some comments...

    *My system at home consists of an MSI 970a-G46 motherboard running on UEFI version 2.5 (the latest.)

    *Already have a decent 8.1 Legacy Windows install in place, but wanted to add a pure UEFI 8.1 installation from my developer 8.1 upgrade iso but found myself without a USB drive of sufficient size to hold all of the Win8.1 installation files.

    *But I did have an extra 320GB SATA II hard drive lying around and I thought I'd try and do my UEFI OS installation from a spare internal SATAII drive instead of the recommended USB drive device.(The size here is arbitrary in that it was all I had...;)A ~150GB drive would work fine, too--you just need enough room for the UEFI install partition and the UEFI Windows installation itself, plus any utilities and things you might like to include in your boot partition.)

    *First thing I did was wipe the 320GB drive completely, of course, convert it to a GPT drive (from MBR), create a ~4GB partition, format it to FAT32, make it primary and mark it active, assign it a drive letter (H:\) and then copy over all the Win8.1 installation files from my developer iso. The remaining ~316GB of drive space I left as unallocated for UEFI 8.1 to install into. I also named the the 4GB volume "UEFI boot" for clarity's sake as I have a bunch of partitions already devoted to various things.

    *Next it was time for a reboot--first critical step in testing my hypothesis. Rebooted and selected the F11 button at the appropriate time to bring up the Boot Device Menu (common to all motherboards.) And suddenly, just as I'd hoped, I had a new boot device entry available: UEFI OS. So far so good, as I'd hoped, my UEFI sees the 4GB GPT, Fat32, primary and active HDD partition as if it is a separate USB UEFI drive device, and begins the UEFI Windows installation.

    *Important distinction, here: At this point in the UEFI OS installation, after the Microsoft installation key is applied, I'm presented with a choice between a clean install and an in-place, upgrade install. The upgrade install is recommended, but I was more interested in the clean install and opted for that choice, since the clean install also lets you select the Win8.1 UEFI version boot partition, and of course it by default chose the ~316GB's of unallocated space left on the original 320GB HDD. Once I selected that I clicked next and I was on my way to a full UEFI install. (In doing a UEFI OS install, if you don't have your UEFI target disk converted to GPT the install will stop at this point and explain to you that UEFI WIndows won't install to an MBR disk. So do your GPT conversion as spelled out above. The UEFI Windows install will automatically take care of the other formatting details like reserve partition, etc.)

    *I strongly suspect that unless you had at first converted your legacy 8.1 install disk to GPT, the upgrade attempt, although recommended by 8.1, would fail, for the same reason you might be stopped before accomplishing a clean UEFI 8.1 install. But I do not positively know that to be the case because I haven't tried it....;) This is an avenue that deserves more thought!

    Would it be possible, I wonder, to actually convert the 8.1 Windows legacy boot disk to GPT and then run a successful in-place upgrade of 8.1 legacy boot to 8.1 UEFI boot?

    I
    ask mainly because the UEFI install process asks me about an upgrade. I'm betting it would tell me to reboot to the OS version I want to update (Legacy.) But I'm still wondering!

    Comments? Suggestions?

    One last thing while I think about it: EasyBCD 2.2, freeware for individuals, makes it super easy to build a boot menu for 8.1 for your legacy and UEFI boot installations. A few button clicks does it.

    (This is the sort of fun I can sink my teeth into...;))

    Also forgot: msinfo32 identifies the new install as...UEFI (not Legacy)...ta-da!...;)

      My System SpecsSystem Spec

  2. #2


    Posts : 5,592
    ME, XP,Vista,Win7,Win8,Win8.1


    Would it be possible, I wonder, to actually convert the 8.1 Windows legacy boot disk to GPT and then run a successful in-place upgrade of 8.1 legacy boot to 8.1 UEFI boot?
    Windows 7 version:
    If you have Windows 7 installed, & two HDD's, you can clone Legacy to UEFI.
    Migrate BIOS x64 install to UEFI. Solved - Windows 7 Help Forums

    Paragon do have a Windows 8 version.
      My System SpecsSystem Spec

  3. #3


    Quote Originally Posted by theog View Post
    Would it be possible, I wonder, to actually convert the 8.1 Windows legacy boot disk to GPT and then run a successful in-place upgrade of 8.1 legacy boot to 8.1 UEFI boot?
    Windows 7 version:
    If you have Windows 7 installed, & two HDD's, you can clone Legacy to UEFI.
    Migrate BIOS x64 install to UEFI. Solved - Windows 7 Help Forums

    Paragon do have a Windows 8 version.
    Thanks! Definitely worth looking at!
      My System SpecsSystem Spec

Installed UEFI 8.1 (clean) boot partition & more...
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