I use PyPy on a Raspberry Pi 3 to drive Octoprint - it's faster than using Python, and more entertaining. The lack of a v7 for ARM was frustrating, and I tried cross-compiling my own. All I found were the instructions for 2.4.0, and I adapted them the best I could. Unfortunately I couldn't hit the combination of Raspbian and Ubuntu (or Debian) that would compile; headers were missing, or something else invariably broke. In frustration, I ended up translating PyPy using a completely emulated system under QEMU running 32-bit Debian Jessie. The good news: it worked! The translation completed successfully. The bad news: It took 48,800 seconds on a fairly current CPU. I don't recommend it for testing. Cheers, Jorge