Alexei's first choice of engine is not surprising at all. He began with a current development version of Stockfish. Although the arm8 binary seems not taking all the juice out of the 64-bit instructions, all his builds are working well with my devices so far and arm7 build performs fast enough to me.
Now all i have to say loudly is "Go Alexei Go!" because there are dozens of other engines waiting to be conqueered, indeed.
GET Stockfish 2017.02.11.ACH for arm7 nopie, arm7 pie and arm8 in a single 7z package