Thanks for your help the other evening - I'm up and running now, though I'm no closer to being able to update the firmware myself.
For linux users I have a (useful?) bash script that beings up a console window and then waits up to 15s for me to plugin the device (that way I see any boot messages). I don't know if this will work on OSX as I don't have a Mac.
I need to update my blog post as I've recently modified the script to allows me to select the which serial device to connect to and baud rate to use.
probably you are connected to board by COM port from different program. You can not be connected to board bye e.g. pymark, putty.
Updater tool must have exclusive access to com port (UART).
Is this the case?