This release uses the HW UART on the Printrboard in place of the USB CDC driver. This enables the use of the new Printrboard Raspberry Pi Link PCB, but causes the USB port on the Printrboard to be non-responsive (unless in boot mode -- in that case, it works fine.)
To build properly, you must change two lines in HardwareSerial.cpp in the Arduino hardware folders. In my case, the file was located:
C:\arduino-0022\hardware\at90usb1286\cores\at90usb1286\HardwareSerial.cpp
line 34: changed TX buffer size to 128
line 134: commented out: //while (tx_buffer_tail == i) ; // wait until space in buffer