The demo program no longer works on my board. I flashed the audio demo from the STM32F4DISCOVERY board firmware package. After playing with it for a while, I flashed the board with the Demonstration hex file from the STM32F4DISCOVERY board firmware package. Now the accelerometer doesn't work. The blink part of the demo works and when I push the button, my computer recognizes the board as a HID device, but tilting and moving the board does nothing. Where do I find the original hex file?