https://bitcointalk.org/index.php?topic=775662.0

What you could do is hook the boards via UART -> USB and try this way.

There is also this github project that used similar way.

Mighty Miner

https://github.com/MightyDevices/mightyminer

Was created for the S1 but I am sure there is possibility of this working on the S3 boards too.

Hope this helps.