The RPi is a toy and a piece of shit. Why anyone would run thousands of dollars worth of equipment off it is beyond me. Toss it and connect your devices to a real PC or laptop.
Trying to do exactly that with Karin's 3.11 build for Mac. Unfortunately, I'm getting a "Hashfast detect (6:3) failed to initialize (incorrect device?)" error.
Update: It's hashing using 3.11 PC build. Must be a Mac driver issue.