I'm trying to figure out which board to upgrade to from the Odroid XU4. Ideally I would have gotten the Odroid N1, but the project was cancelled. The think I liked most about this board was 2 on board SATA ports. Odroid will not be releasing information about their next board until mid October which means by the time there's a board release with a stable system it'll be well into next year, which does not meet my timeline. Pine64 recently released the RockPro64 which seems somewhat compelling. It comes with a RK3399 SoC and can be upgraded with 2 SATA ports via PCIe slot, you can also power 3.5" hard drives through the board itself. However, it has a very large form factor and the PCIe card sits vertically which to me isn't very ideal. Pine seems to have a very large community and they seem to be quickly working towards a stable release for this board. Looking at the NanoPC-T4 It advertises that the M.2 M Key can be used for a SATA interface. The NanoPC-T4 also have a very nice small form factor so I'm trying to figure out if it will meet my needs. My questions are as follows:

1. Does Friendlyarm have a good community? Will this board ship with relatively bug free distributions and appropriate drivers?

2. Does Friendlyarm sell M.2 M Key Sata adaptors? Is the one or two sata ports on these adaptors? Can the board power 3.5" HDDs like the Rockpro64? If Friendlyarm doesn't sell an adaptor like this where can i find one? Is it stable, has someone tried it out? What kind of speeds can you get through this type of interface?

3. How is the 4k 60 playback on this board?

4. The biggest difference in specs between the Rockpro64 and the NanoPC-T4 is that the NanoPC has LPDDR3 vs the Rockpro's LPDDR4, will this make a noticable difference in performance?