With the HashBuster Micro removed from the equation (and hashing on a PC) the Rpi works great.
Glad to hear you got it sorted.
Glad I didn't bother buying a HashBuster Micro and got an ASICMiner Cube instead...
Got a cube also works fine on mine-proxy in windows
I have this as startup settings
#!/bin/bash
sleep 10
/usr/bin/screen -dmS miner /opt/minepeon/bin/bfgminer --http-port 8330 -c/opt/minepeon/etc/miner.conf
When cube is pointing to Pi on port 8330 (2x) I see nothing on Pi and nothing on connected pool.