Remove the 10K resistor that appears where the red X is on the photo. You should double check with a multi-meter that you're removing the correct part. It is connected to the B1 port. This B1 port forms part of the configuration of the TGAM1 board. In the MindFlex this 10k resistor connects the B1 port to GND which configures it in normal mode at 9600 bps.
Solder a connection on to the B1 port, then you can add a new 10K resistor that connects the B1 port to VCC. This enables raw output mode at 57600 bps.
You connect to the Arduino in the same way, but you can't use the Arduino Brain Library with this configuration. I'm working on an update for this.
The TGAM1 chip still sends the summary data packets that you get in normal mode once per second, but now you will also get a packet containing the raw EEG reading 512 times per second, approximately once every 2ms.