Creating USB Media for MDT installation with boot WIM > 4GB

Ax Murdarah 101 Reputation points
2020-12-02T16:51:00.587+00:00

We have a working installation of MDT with the lastest AIK, which can successfully build laptops using a PXE boot. The objective is to be able to perform the build from USB media, to allow builds to tale place away from the office.

I have followed the steps in https://learn.microsoft.com/en-us/windows/deployment/deploy-windows-mdt/deploy-a-windows-10-image-using-mdt#use-offline-media-to-deploy-windows10 to create offline media. To give some information, the offline media that is created has two image files. One image file is the operating system to deploy, held under "Deploy\Operating Systems\WIN10REF2004-1" which is split into 1GB swm files, by the setting of " <SkipWimSplit>False</SkipWimSplit>" in the settings.xml file. The other image file is the one that is loaded into a Ramdisk when WinPE boots, and this ends up as "LiteTouchPE_x64.wim" in "Deploy\Boot", and is 4.8GB in size. The Total size of the deployment folder is about 35GB.

A couple of points to note:

  1. The Total size of the deploy folder exceeds the maximum size of a FAT32 partition
  2. The size of the boot WIM at 4.8GB exceeds the maximum size for a file in a FAT32 partition
  3. Although I know that a UEFI PC can boot from NTFS if the Vendor provides the driver, the Lenovo X280 I want to build will not entertain booting from a 64GB NTFS formatted USB device
  4. The Lenovo X280 will boot from a generic PE USB device

I have attempted to use Rufus to use UEFI NTFS disc creation, which loads in a driver for NTFS. I think this fails with insufficient memory to load Ramdisk (the laptop has 8GB RAM)

This seems to leave me in a situation where I have to have 2 partitions. A smaller FAT32 partition to enable the boot, and a larger NTFS partition to hold the majority of the Deploy folder. I can think of two possible methods to achieve this, neither of which I have been able to make work:

  1. Split the boot WIM image and make PE boot from that. I have used DISM to split the WIM into SWM files and copied these onto the USB disc in place of the WIM. I consistently get device missing errors. To be honest, I do not know how to make the BCD point to these SWM files - at present the MDT offline build creates a BCD which references "device ramdisk=[boot]\Deploy\Boot\LiteTouchPE_x64.wim"
  2. Make the boot process on the USB stick reference the 4.8GB LiteTouchPE_x64.wim in a location on the second (NTFS) partition. I do not know if this is possible

I would be glad of any suggestions on how to make this work, or of a better way

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Microsoft Deployment Toolkit
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A collection of Microsoft tools and documentation for automating desktop and server deployment. Previously known as Microsoft Solution Accelerator for Business Desktop Deployment (BDD).
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  1. Ax Murdarah 101 Reputation points
    2020-12-04T09:04:47.723+00:00

    I have got past this now - I was trying to solve the wrong problem. The replies led me to considering why my boot WIM file was so large. Basically I had loaded too many drivers in the WinPE properties of the MEDIA entry in MDT. I changed this to select the WinPE x64 selection profile and only Network and Storage drivers, and the resultant WIM was about 600MB which does not cause this issue. I still have to use a 2 partition USB stick, but that is because of the size of the deployment share

    Thanks for the replies

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  1. Rick Someone 411 Reputation points
    2020-12-02T17:19:03.637+00:00

    I read the info from the link. When I make USB drives to do offline imaging, I create the Media folder first. Then, I format my USB using diskpart.

    1. Diskpart
    2. List disk
    3. Select disk
    4. clean
    5. create partition primary
    6. active
    7. format fs=ntfs
    8. assign

    Then I merely copy the contents of my Media Contents folder to the USB. I've never had an issue of
    having to use FAT32 or splitting the WIM. If the contents are over 8G I get a 16G USB drive.

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  2. Ax Murdarah 101 Reputation points
    2020-12-02T17:32:39.25+00:00

    Thanks for the suggestion, RickSomeone. Those are the steps I followed when I said ‘the Lenovo X280 (with UEFI BIOS) will not boot from an NTFS formatted USB’

    I think it is down to the vendor and the firmware they supply. If yours work, that is great, but unfortunately does not help me.

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  3. Rick Someone 411 Reputation points
    2020-12-02T17:37:55.74+00:00

    Right on. I think I am very fortunate that we only work with Dells and Panasonic computers.

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  4. Joy Qiao 4,886 Reputation points Microsoft Employee
    2020-12-03T09:59:17.813+00:00

    Hi,

    I noticed other customer tried to boot computer from FAT32 with NTFS partition by split wim file into 2 parts, one for sources folder, another partition for other folders. Please try to check if it works on your side.

    USB install media with WIM file larger than 4GB

    I would also recommend to contact with Lenovo support if they have related driver for support NTFS USB.

    Please note: Information posted in the given link is hosted by a third party. Microsoft does not guarantee the accuracy and effectiveness of information.

    Bests,

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