Windows 8 and 8.1 Forums


UEFI Bootable USB Flash Drive - Create in Windows

  1. #260


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


    Quote Originally Posted by toerk View Post
    That's because it's x86 + x64 in one ISO
    Any way to seperate them?
    YES, you could buy the legal Microsoft official ISO/DVD.

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  2. #261


    Sydney, Nova Scotia, Canada
    Posts : 6,489
    Windows 10 Education 64 Bit


    Quote Originally Posted by Akeo View Post
    Actually, Microsoft did release official Windows 8 ISOs that had a file that was > 4GB, and thus incompatible with USB UEFI boot.
    One of the Windows x64 8 developer preview was one of those. Thus it's just not an issue for unofficial ISOs. And I think there exists other MSDN ISOs that have > 4GB wim files, though I may stand corrected on that.

    Thus, we've got some choice on who to place the blame on:
    1. Microsoft, for designing a filesystem (FAT32) that they should have realized right from the start, would end up being too limiting too quickly, due to its 32 bit nature, even more so as they designed FAT32 to overcome the limitations of the previous FAT filesystem.
    2. Intel and the UEFI committee, picking FAT32 as the filesystem of choice for UEFI bootable partitions, despite being acutely aware that UEFI had to work with 64 bit and large files.
      Considering that Intel & co. managed to waive the licensing agreement for the use of FAT32 (see here), it's hard to believe that they had much of a legal incentive for using FAT32, when they probably could have stricken a similar agreement for either exFAT or NTFS, none of which suffer from the 4GB limitation. exFAT was actually begging to be used for that purpose, and Microsoft was also promoting it, so why they didn't go exFAT is a major mystery. Or, if they didn't want to fall into a a Microsoft licensing agreement, they could have settled on using the more open UDF filesystem, which is designed for more than optical media, and works equally well for USB flash drives.
    3. Microsoft (again) and others, producing ISOs that they know have no chance to be bootable from USB, due to the presence of a >4GB file. They probably could devise a way to split wim's into <4GB chunks if they wanted to.


    Of course, there's also the possibility that Microsoft may have required a more constraining licensing agreement for the use of either exFAT or NTFS in UEFI, maybe because they got annoyed that their extortion scheme for FAT32 licensing got rightfully shot down initially (though, without insider info, it's difficult to do anything but speculate on that).

    Anyway, what this all means is:


    • There's nothing Rufus can do right now, about a limitation that is purely between an UEFI design decision and a Microsoft filesystem limitation.
    • If UEFI ever decide to pay heed to how their decision to go with FAT32 is actually inconveniencing users, they may decide to add support for UDF (or exFAT), alongside FAT32, for bootable partitions. Right now, I am not aware of any steps having been taken in that direction, and even if that was the case, this won't mean squat for current UEFI firmware implementations, as vendors aren't going to spend time retrofitting them for UDF/exFAT support.
    • Maybe there is some arcane way to fool an UEFI system into treating an UDF formatted USB Flash drive as optical drive, in which case you could get away with using UDF instead of FAT32. Outside of someone showing a verifiable proof of concept, I wouldn't spend too much time on that though.


    All in all, it looks to me like the only way you currently have to boot an EFI ISO with a >4GB file is to burn it, and get your hands on an optical drive...
    I can install in UEFI mode with an NTFS formatted thumb drive. That's the way the Windows 7 DVD download toll formats the drive and what I use to make my bootable Windows 7 and Windows 8 thumb drives. Granted, for most people that does not work and they need a fat32 formatted drive. It's not etched in stone though as I've done it with NTFS drive.

    I wasn't aware that there was a 4 gig file in the ISO, so my apologies for that slip up. Going by the ISO file sizes on TechNet, that didn't seem possible.
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  3. #262


    Ghent, Belgium
    Posts : 13
    Windows 8 Enterprise 64-bit


    Thanks for the info,
    apparently this ISO was a kind of the integrated ISOs, therefore I got rid of it and got a legit copy of Win8 x64 Pro only and could install Windows in UEFI. Issue solved :P
      My System SpecsSystem Spec

  4. #263


    .ie
    Posts : 35
    Windows 7 x64


    Quote Originally Posted by alphanumeric View Post
    I can install in UEFI mode with an NTFS formatted thumb drive. That's the way the Windows 7 DVD download toll formats the drive and what I use to make my bootable Windows 7 and Windows 8 thumb drives.
    Are you sure???

    I have just tried that the Windows 7 DVD again, and it doesn't work at all when trying to boot NTFS in UEFI mode on an UEFI 2.0 platform.
    I previously formatted the drive as GPT/NTFS and the Microsoft tool kept those settings after formatting, but this won't boot from UEFI at all on my platform.

    Does your UEFI firmware have NTFS support? Or are you sure you weren't actually booting into regular MBR mode (which UEFI firmwares will usually allow, but then you won't be able to install the OS in UEFI mode)?

    If UEFI/GPT/NTFS is actually supported by some firmwares, I'd like to know, as it may be worth adding such a mode to Rufus. But I'm not aware of UEFI firmwares out there that can boot NTFS in UEFI mode...
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  5. #264


    Sydney, Nova Scotia, Canada
    Posts : 6,489
    Windows 10 Education 64 Bit


    Quote Originally Posted by Akeo View Post
    Quote Originally Posted by alphanumeric View Post
    I can install in UEFI mode with an NTFS formatted thumb drive. That's the way the Windows 7 DVD download toll formats the drive and what I use to make my bootable Windows 7 and Windows 8 thumb drives.
    Are you sure???

    I have just tried that the Windows 7 DVD again, and it doesn't work at all when trying to boot NTFS in UEFI mode on an UEFI 2.0 platform.
    I previously formatted the drive as GPT/NTFS and the Microsoft tool kept those settings after formatting, but this won't boot from UEFI at all on my platform.

    Does your UEFI firmware have NTFS support? Or are you sure you weren't actually booting into regular MBR mode (which UEFI firmwares will usually allow, but then you won't be able to install the OS in UEFI mode)?

    If UEFI/GPT/NTFS is actually supported by some firmwares, I'd like to know, as it may be worth adding such a mode to Rufus. But I'm not aware of UEFI firmwares out there that can boot NTFS in UEFI mode...
    Yes I'm sure, the EFI system partition is present and I have the UEFI Firmware Options as shown here, UEFI Firmware Settings - Boot to from inside Windows 8. The thumb drive was created with the Windows 7 DVD download tool, which formats the drive in NTFS. BIOS shows UEFI for that drive in my boot menu. ASUS K75DE laptop, latest BIOS.
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  6. #265


    .ie
    Posts : 35
    Windows 7 x64


    I can't help but still be sceptical, sorry.

    Can I ask you to check one thing? Using any Windows installation ISO for Windows 7 or later, can you please create a bootable NTFS based USB, using the Windows 7 DVD tool, then, once it's completed, delete the 'bootmgr' file at the root of the drive (but not 'bootmgr.efi') and see if you can still boot that USB on your ASUS system.

    This should tell for sure whether MBR or UEFI is being used for booting that NTFS drive.
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  7. #266


    Sydney, Nova Scotia, Canada
    Posts : 6,489
    Windows 10 Education 64 Bit


    I don't need to do that, I may try it but I don't see the need. My thumb drive is formatted in NTFS and Windows is installed in UEFI mode. I just did an Enterprise install to that laptop today.
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  8. #267


    .ie
    Posts : 35
    Windows 7 x64


    Well, I can still see a couple possibilities where:
    1. ASUS fiddled with their UEFI firmware to fake an UEFI boot while going through an initial MBR one (by checking if there's a bootmgr and bootmgr.efi and pretending it can do an UEFI boot).
    2. Microsoft fiddled with their MBR installation process so that, when it starts in MBR mode, and detects an UEFI BIOS, it switches to UEFI mode (which, quite frankly, is something they should be doing in the first place anyway).


    Since I can't test this UEFI NTFS support at all, as it doesn't appear to work on the UEFI platform I have, I'd like to have some insurance that there's no trickery involved before I invest time trying to add it in Rufus...

    [EDIT] PS: I'm not asking you to reinstall Windows here. Just see if the USB boots with bootmgr removed.
      My System SpecsSystem Spec

  9. #268


    Quote Originally Posted by Akeo View Post
    Well, I can still see a couple possibilities where:
    1. ASUS fiddled with their UEFI firmware to fake an UEFI boot while going through an initial MBR one (by checking if there's a bootmgr and bootmgr.efi and pretending it can do an UEFI boot).
    2. Microsoft fiddled with their MBR installation process so that, when it starts in MBR mode, and detects an UEFI BIOS, it switches to UEFI mode (which, quite frankly, is something they should be doing in the first place anyway).


    Since I can't test this UEFI NTFS support at all, as it doesn't appear to work on the UEFI platform I have, I'd like to have some insurance that there's no trickery involved before I invest time trying to add it in Rufus...

    [EDIT] PS: I'm not asking you to reinstall Windows here. Just see if the USB boots with bootmgr removed.
    My experience is that creating a UEFI Boot disk thumb drive with Rufus or manually. For my Asus G75 I had to invoke the boot menu and then select the UEFI USB drive. I know this because I clicked on the straight up USB Drive and it installed the MBR Version!! even though my drive was already GPT. I didn't notice this for a day or so. Then I had to start over selecting the UEFI USB drive and it installed UEFI GPT, Thumb drive was FAT32, I was never able to install win 7 HP 64 with a NTFS USB every time I installed I had to use USB Fat 32 thumb drive or I would end up with a MBR installation. I never tried with Win 8.1 just went with the fat 32 format USB
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  10. #269


    Sydney, Nova Scotia, Canada
    Posts : 6,489
    Windows 10 Education 64 Bit


    Quote Originally Posted by Akeo View Post
    Well, I can still see a couple possibilities where:
    1. ASUS fiddled with their UEFI firmware to fake an UEFI boot while going through an initial MBR one (by checking if there's a bootmgr and bootmgr.efi and pretending it can do an UEFI boot).
    2. Microsoft fiddled with their MBR installation process so that, when it starts in MBR mode, and detects an UEFI BIOS, it switches to UEFI mode (which, quite frankly, is something they should be doing in the first place anyway).


    Since I can't test this UEFI NTFS support at all, as it doesn't appear to work on the UEFI platform I have, I'd like to have some insurance that there's no trickery involved before I invest time trying to add it in Rufus...

    [EDIT] PS: I'm not asking you to reinstall Windows here. Just see if the USB boots with bootmgr removed.
    I'll give it a go when I have time. I just reinstalled on my laptop so I want to finish tweaking that install to what I want first. I've installed with Fat32 and NTFS thumb drives and it comes out the same way each time. All the indications are Windows is installed in UEFI mode. As far as the BIOS goes it doesn't look any different than any other BIOS I have used. I do believe this laptop originally shipped with Windows 7 and a non UEFI BIOS. Maybe it isn't a true, full on UEFI BIOS?
    I have some other posts in this thread on fat 32 vs NTFS. UEFI Bootable USB Flash Drive - Create in Windows
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UEFI Bootable USB Flash Drive - Create in Windows
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