From Fedora Project Wiki

Fedora 21 Alpha for AArch64

Download the disk image

wget http://armpkgs.fedoraproject.org/compose/21_Alpha_RC1/Server/aarch64/iso/Fedora-Server-DVD-aarch64-21_Alpha.iso

For the Applied Micro Mustang (X-Gene)

Network Installation

USB Installation

It is possible to start an installation of Fedora 21 Alpha with out going through the steps of setting up a PXE server and rather initiating a network installation through a USB drive formatted appropriately. You can create this yourself using the provided installation media, or you can use the prepared image:

https://pwhalen.fedorapeople.org/Fedora/21/aarch64/Fedora_21_Alpha_Installer.img.xz

Copy the USB image to your media, you will need at least a 512M USB stick.

MEDIA= # location of your USB device
xzcat Fedora_21_Alpha_Installer.img.xz | sudo dd of=$MEDIA

Insert the USB device into the bottom port located at the back of the Mustang board (below the network port), power on the machine and interrupt the boot, chooseing the 'shell' option. Once at the EFI shell:

FS0:\EFI\BOOT\BOOTAA64.efi

This will boot the Fedora 21 Alpha installer, choose either VNC or Text installation.