Windows 10 Build 15035 Media Builder Install Direct

Windows 10 Build 15035 is a rare, leaked pre-release version of the Creators Update that is significant because it is the only known build compiled for ARMv7 (32-bit ARM). It is primarily used by enthusiasts to unofficially install Windows 10 on older hardware like the Surface RT. 

Because this is a leaked, unofficial build, there is no official Microsoft "Media Builder" for it. You must typically use a community-developed "Image Builder" or manual deployment script to create a bootable installer.  How to Build the Installation Media 

To install this build on a device like a Surface RT, you generally need to follow these steps found in community guides like i12bretro's tutorial: 

Obtain the ISO/WIM: You must find the Build 15035 ARM32 files (often hosted on sites like BetaArchive). windows 10 build 15035 media builder install

Use a Secure Boot Exploit: Devices like the Surface RT are locked. You must use a "Golden Keys" exploit or a specific UEFI exploit script (e.g., Yahia's installer) to allow non-official OS booting. Prepare the USB: Format a USB drive as FAT32.

Use a tool like Rufus or manual diskpart commands to make it bootable.

Apply the install.wim image to the USB using a deployment script specifically designed for the ARM32 build. Windows 10 Build 15035 is a rare, leaked

Boot from USB: Hold the Volume Down button and press Power on the Surface RT to boot into the installation environment.  Important Limitations 

Unsupported: This build is highly unstable and will never receive security updates.

No Prism: Unlike modern Windows on ARM (which is 64-bit), this 32-bit build lacks an emulation layer to run standard x86 (.exe) apps. Why Use a Media Builder Instead of a Standard ISO

Driver Issues: Many hardware components (like Wi-Fi or GPU acceleration) may require manual driver injection during the media building process. 

Update Microsoft Surface RT Tablet to Windows 10 [Unofficial Upgrade]

Phase 2: Installing Windows 10 Build 15035

Appendix A: Sample Unattend.xml Snippet for Media Builder

<?xml version="1.0" encoding="utf-8"?>
<unattend xmlns="urn:schemas-microsoft-com:unattend">
    <settings pass="windowsPE">
        <component name="Microsoft-Windows-Setup" processorArchitecture="amd64">
            <DiskConfiguration>
                <Disk wcm:action="add">
                    <CreatePartitions>
                        <CreatePartition wcm:action="add">
                            <Order>1</Order>
                            <Type>Primary</Type>
                            <Size>100</Size>
                        </CreatePartition>
                    </CreatePartitions>
                </Disk>
            </DiskConfiguration>
        </component>
    </settings>
</unattend>

Why Use a Media Builder Instead of a Standard ISO?

If you have ever downloaded a leaked Windows build in the past, you would simply mount an ISO file. However, for Build 15035, most available sources are UUP files (encrypted, differential update packages). The standard ISO does not exist in the wild.

A media builder performs three critical functions:

1. Decryption: Unlocks Microsoft’s UUP encryption.
2. Conversion: Transforms UUP files into a standard install.wim (Windows Imaging Format).
3. Packaging: Creates a bootable ISO or USB drive.

Attempting to install Build 15035 without a media builder will result in missing file errors or a "source not found" message during setup.