How To Make A UEFI Bootable Flash Drive

Creating a bootable drive for a UEFI/EFI machine is actually quite simple. All you need to do is format the flash drive and set it up then dump your files on it from any bootable OS CD like Windows Server 2012 or Windows 8 or any of your favourite bootable CD images you use for diagnostics. Please remember that this is for UEFI systems not BIOS based system that still require MBR and such..


  1. Open a elevated Command prompt Win+X, Command Prompt (Admin))
  2. C:\Winodws\system32> diskpart     Run the DiskPart tool
  3. DISKPART> LIST DISK       Type this command to get a list of attached disks to your machine
  4. In the list of disks, look at the size column. You should see a drive that should almost matches the size of your drive. For instance my drive is 16 GB but shows up as 14 GB this is because of partitioning information take a bit from the drive and this is expected. So in my case I can tell my drive is DISK 1

  5. DISKPART> SELECT DISK #       Make sure you change # to your disk number
  6. DISKPART> LIST DISK      We are running LIST DISK again to make sure the correct drive is selected. You should see an asterisk beside the drive that you selected. The reason we need to make sure the correct drive is selected is because the next command will destroy all data on the drive. PLEASE MAKE SURE THE CORRECT DRIVE IS SELECTED!!
  7. DISKPART> CLEAN       This command will wipe the drive clean. I hope you selected the right disk above…
  8. At this point we have a clean drive. We will now need to setup a partition and format it. There is a very important thing to note, UEFI will only boot off a FAT32 partition. The reason this is an issue is because FAT32 can only support a maximum of a 32 GB partition. Now most people creating a bootable pen drive will only have a 8 GB flash drive or even a 16 GB flash drive. The problem is only if your drive is larger than 32 GB. If your drive is smaller than 32 GB than just skip to step 9 and ignore the rest of this paragraph.

    If your drive is larger than 32 GB you will have to modify the command below so that it limits the partition size to be less than 32 GB. If you don’t tell it a limit it will create a partition the size of the whole drive and in step 12 when you try to format the partition as FAT32 you will get an error that the partition is to large to support the File System specified.  To fix this we will add “SIZE=31744” after the command in step 9. This will create a 31 GB partition if you do the math (31744/1024), I use 31 GB just to make sure I am under the 32 GB limit.

  9. DISKPART> CREATE PARTITION PRIMARY   – make sure you add on the SIZE option if your drive is larger than 32 GB.
  10. DISKPART> SELECT PARTITION 1   This will select the partition we just created.
  11. DISKPART> ACTIVE      This will mark the partition as an active partition.
  12. DISKPART> FORMAT QUICK FS=FAT32     This will format the volume quickly and user the FAT32 format for the File System
  13. DISKPART> ASSIGN    This will assign a drive letter to your drive.
  14. DISKPART> EXIT   You can now exit diskpart and close your command prompt window.
  15. You can now place any UEFI bootable files (I.E. copy all files from your Windows 8 DVD) on the drive and Bob’s Your Uncle!!


© Caspan 2014