The Marvell ESPRESSOBin (manufactured by GlobalScale) is a single board computer aimed at networking, storage, and connectivity. It features a Marvell ARMADA 3720 chip which can be used with Debian's arm64 port.

The Marvell ESPRESSOBin is available to order. Some of the early Kickstarter orders have been sent out already.

U-Boot

U-Boot support has been accepted for 2017.05.

Kernel

Initial support for the Marvell ESPRESSOBin can be found in the 4.10 kernel. The current 4.12 kernel in unstable, backports boots on the ESPRESSOBin including Network and SDHCI support. Further patches have been proposed to increase the functionality, including these patch sets:

UBOS Docs

The UBOS docs have a default uboot environment which I found useful as I forgot to dump mine!

https://ubos.net/docs/users/installation/espressobin.html

Armbian

There is a work in progress Armbian port.

https://www.armbian.com/espressobin/