PINE64 ROCKPro64

The PINE64 ROCKPro64 is Article description::a Rockchip RK3399 (ARMv8-A, Cortex-A72/A53 big.LITTLE) based, exceptionally libre software friendly SBC. It supports booting and even 3D hardware acceleration without any proprietary or closed source firmware blobs. The vendor focuses solely on hardware so there's no official software support. However, a vibrant and open community that provides extraordinary libre software support gathered around their products.

Installing Gentoo
Consult PINE64 ROCKPro64/Installing Gentoo for instructions on how to install Gentoo on the Pine64 ROCKPro64.

Issues
Depending on board revision and U-Boot version setting  (which enables boot from USB) in U-Boot might cause the boot process to get stuck at   even when booting from SDXC or eMMC.

External resources

 * PINE64 ROCKPro64 on linux-hardware.org