Deployment Options for UEFI based Computers

Today’s blog will discuss support for UEFI with Microsoft Deployment Toolkit and other deployment tools. First we should discuss why this change is occurring. Today’s BIOS has been around for a long time. Some of the limitations include:

  • 16bit code
  • 1mb address space limitation
  • Slow option ROM initialization
  • MBR maximum bootable disk size is 2.2tb


Unified Extensible Firmware Interface spec replaces the existing BIOS with brand new scheme. More information on UEFI can be found at One of the improvements will be that it will remove the limitation around disk sizes. It will support GUID Partition Table (GPT) which allows for max of 16.8 million TB. 


Windows only supports UEFI with 64bit Windows. There is no support for X86 OS (requires legacy BIOS fallback mode). Improvements with UEFI in Windows will allow for the following:

  • Faster initial booting(no need to use Int13 BIOS calls)
  • Faster resume from hibernate
  • Multicast PXE boot

Many machines such as IBM, HP, and Dell are shipping today with support for UEFI. The following summarizes the support for UEFI in Microsoft deployment tools:


Windows Deployment Services: UEFI is supported

Microsoft Deployment Toolkit 2010 Update 1: Unsupported since it was not fully tested. At the time MDT was created there no production machines available for us to test.

System Center Configuration Manager (ConfigMgr): UEFI is unsupported. 


If the computer emulates a “legacy” BIOS it should work fine. For example on some IBM servers they have instructions similar to this.

To install the operating system in legacy Mode, boot to the F1 menu options. Select Start Options and Legacy Only

You should contact the manufacturer of the computer to determine if it supports a legacy option and any additional steps to enable this.


Additional Information around manual installs to UEFI computers

Scott McArthur

Senior Support Escalation Engineer

Microsoft Enterprise Platforms Support