WinPE network adapter only works after manual drvload, despite driver present in SCCM boot image

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Hi,

I am building an SCCM OSD environment and have encountered an issue where the wired network adapter is not initialised automatically after WinPE loads.

Environment

• Microsoft Configuration Manager Current Branch 2603
• Current Windows ADK and WinPE add-on
• x64 WinPE boot image
• PXE-enabled Distribution Point
• Lenovo ThinkBook 14-IIL, Type 20SL
• Realtek PCIe GbE network adapter
• Realtek driver: rt640x64.inf
• Driver version: 10.43.723.2020

Symptoms

The device successfully:

• Contacts the correct PXE server
• Downloads the x64 boot image
• Starts WinPE
• Reaches the Configuration Manager screen

However, the Task Sequence Wizard does not continue.

The task-sequence log shows that WinPE repeatedly fails to download the PXE variable file from the PXE server:

Unable to download PXE variable file. Exit code=14.

Failed to download PXE variable file after 6 retries.

PxeGetPxeData failed with 0x8004016c.

Running ipconfig at this point shows no active Ethernet adapter.

Troubleshooting completed

I have:

• Imported the Realtek PCIe GbE driver into SCCM
• Added the driver to the x64 boot image
• Confirmed the driver is listed under the boot image’s Drivers tab
• Reloaded the boot image using the current Windows ADK
• Updated the Distribution Point
• Confirmed the boot image is distributed successfully
• Confirmed the PXE copy of the WIM has a current timestamp
• Mounted the distributed WIM and confirmed the driver is present:

Driver: oem5.inf

OriginalFileName: rt640x64.inf

ProviderName: Realtek

ClassName: Net

Version: 10.43.723.2020

The driver does not appear to bind or initialise automatically during WinPE startup.

Manual workaround

If I copy the complete Realtek driver folder to a USB drive and run:

drvload "D:\LAN_V02\rt640x64.inf"

wpeutil InitializeNetwork``

The driver loads successfully, the device receives a valid DHCP address, and it can reach the SCCM server.

The task sequence then proceeds successfully if the driver is loaded before the PXE variable-file retries expire.

Question

Why would a network driver work correctly when loaded manually with drvload, but not initialise automatically when the same driver is confirmed as present in the distributed WinPE boot image?

Is there a recommended way to make this driver load automatically that will scale across multiple laptop and desktop models?

I would prefer to avoid:

• A model-specific prestart command
• Manually loading drivers from USB
• Adding complete model driver packs to the boot image

Any advice on WinPE driver ranking, Plug and Play initialisation, driver versions, or recommended SCCM boot-image practices would be appreciated.