Compàñero Tofi
En las instrucciones del firmware 3.5 de la pagina de Xtreamer da a entender de que es normal que se ponga en marcha al poner el cable de corriente.
Hay varios compañeros que lo han comentado en este foro.

To install just download and copy install.img to the root of a USB stick.
* Go to your Prodigy, turn it off by unplugging the power cord for few sec.
* Put the cord back but do not power the machine on.
* Plug the USB stick to a USB port at the back panel.
* When the machine is OFF press the power button for about 10 sec (you will see that the blue LED light is turning on but still keep your finger pressed on the power button until the power LED is turned off).
* When the LED is off you can release your finger and let it start flash the firmware.