I'm currently running cpu multi miner on RaspberryPi 3 with raspbain lite. Each card will run around 25 hashes per second using the ARM possessor only. This requires alot of code optimization but it can be done. Unfortunately the RaspberryPi GPU lacks support for miners to develop software for, however you can mine on the Mali450 GPU found on the OrangePi and Tinkerboard. At this point all Mali GPU miners are modified from existing software with no official support. I just ordered my first OrangePi so I can't speak from personal experience but I've been told you can get up to 50 hashes from the gpu.... add the 25 from the ARM processor and that's not a bad result from $17-$35 hardware that consumes about 3 watts.