Procedure

UEFI requires USB media to be in FAT32 format, which has a 4GB file size limitation. The install.wim file for Server 2012R2 is about 4.5GB, so needs to be split up as follows:

Step 1. Split install.wim image

• Extract ISO contents, go to the Sources folder and locate the install.wim file
• Copy the file to a separate folder (e.g. C:\Temp)
• Open a Powershell window with admin rights and browse to this newly created folder
• Run the following command:

Dism /Split-Image /ImageFile:install.wim /SWMFile:install.swm /FileSize:4000

This will create two files: install.swm and install2.swm

• Copy these two files to the Sources folder and delete the install.wim file

Step 2. Format USB key

• Run cmd

> DISKPART

> LIST DISK

> SELECT DISK (pick appropriate disk)

> CLEAN

> CREATE PARTITION PRIMARY

> SELECT PARTITION 1

> ACTIVE

> FORMAT FS=FAT32 QUICK

> ASSIGN

> EXIT

• Copy all the folders from extracted ISO into the USB stick. Now you should be able to boot and install Windows from it