My Rainbowduino 3.0b gives me the tk500_getsync() error while uploading a .ino file unless I re-burn the bootloader from another Arduino first using Arduino ISP.
I have to do this EVERY TIME I want to change any code on the Rainbowduino 3.0b.
Why must I do this each time? I own several Arduinos from different manufacturers and this is the only one that seems to exhibit this behavior.
It seems as though loading a sketch into the Rainbowduino from the Arduino IDE software overwrites the bootloader or something and makes it impossible for it to check if the serial interface is supposed to load new code or not.
I am using only the example sketches provided for the Rainbowduino, so I don’t understand what could be wrong here.
Do I have a defective board?
I have posted my workaround here: forum.arduino.cc/index.php?topic=170327.msg2295805#msg2295805