MMN-o from Umea Hackerspace successfully recovered his Proxmark3 using the Bus Pirate:
Sure, there are cheap, hackable alternatives that connect to the parallell port, but that interface is unfortunately of a pretty bygone era. So given that I did not have access to a true parallell port at the time, I had to keep looking for alternatives. Essentially anything that worked with the flashing and debugging utility OpenOCD would be good, and something I could find nearby would be even better! And the OpenOCD list of supported interfaces contained among many others the Bus Pirate, a handy open hardware design that helps hackers with serial communication of just about any kind.
Get an assembled Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.
I can confirm this works. I recently programmed a hand assembled proxmark 3 following that tutorial and everything went allright.