How to create custom partitions on a usb key (boot key) on Windows 8.1

Windows 8.1 does not allow you to create a custom partition size on a USB key (needed for some netbooks to boot from USB key).

    1. Open Elevated Command Prompt
    2. Run diskpart
    3. Type Rescan
    4. Type “list disk” to show all disks.
    5. Type the disk that you want to partition (in my case partition “4”). Make sure you select the right disk or your will delete your data with no prompts).

Enter these commands (note my custom partition size if 3072, change to your custom size).


Create Part Primary size=3072



Format fs=fat32 quick Label=”Boot”

Create part primary


Format fs=fat32 quick Label=”Deploy”