Allwinner A64 - ARM Cortex A53 SoC
The Allwinner A64 is a quad-core SoC with MALI400 GPU support.
Free Software Support
Despite the usual GPL violations in Allwinner's SDK, Free Software support in the form of mainline bootloader and kernel support is continually improving. Of particular note is the U-Boot support for functionality that previously required the proprietary "boot0" payload, specifically this commit.
As always with Allwinner products, the Linux mainlining status is worth checking to see what the community-developed software supports.