I'm running a Raspberry Pi B+ with Minera.  32 Gridseeds on an Eyeboot 49 port hub.  Gridseeds are running at 875 each, pushing about 11.5-12 M all together.  Try Minera - It works for me (with a limit of 32 Gridseeds - Trying to overcome that limit, but not sure how...  Be well! JimiH