Slow network transfer when using virtual machine with EFI BIOS during PXE boot and download of WIM image using TFTP from Windows Deployment Services

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• Slow network transfer when using virtual machine with EFI BIOS during PXE boot and download of WIM image using TFTP from Windows Deployment Services
• If you attempt to PXE boot a virtual machine that uses EFI firmware, with a vmxnet3 network adapter and WDS, and you have not disabled the variable Windows extension option in WDS, the virtual machine might boot extremely slowly.

Resolution

This issue is resolved in

• ESXi 6.5 Patch Release ESXi650-201811002, available at VMware Patch Downloads. For more information on downloading patch, see 
  How to download patches in Customer Connect
• ESXi 6.7 Update 1, available at VMware download

Note: If E1000 or E1000e virtual adapters are in use, switch to vmxnet3 driver for the given use case to avail the solution after deploying one of the above ESXi versions.