The previous sections guided you to your first system images, ready to be flashed to your hardware. These images will be deployed to the device memory. The Nexus 6 has an internal Nand memory. The UDOO has a pretty standard SD card. The first step of the deployment is switching the device into the bootloader mode.
Bootloader mode is a particular state of the device that allows us to transfer and deploy a system image to the device itself, using the fastboot utility. Every device running Android has this mode, but not every device will let us access it. Some devices come with a locked bootloader, for security reasons or simply because of a short-sighted manufacturer.
Obviously, we will be able to access the bootloader on our devices: Google is a generous manufacturer and every Nexus device comes with an unlocked or unlockable bootloader; UDOO, as a development board, is designed to be developer friendly, as well.
