As was mentioned earlier, there are holes for the header pins for a serial line on the PCB right next to the SD card slot.
Using a TTL serial converter with 115.2kbps will give you a root console into some Android based image. Auto-mounts USB drives and SD cards; was able to use dd to dump the firmware image in a couple of minutes onto an SD card.
Are there different versions around? How to identify which version I have?