The KTunerFlash V2 Touch is a high power device due to the LCD and LEDs. It is required to have a high power USB port when connected to the unit or it may restart due to brown out voltage thresholds. See details below.
The unit will brownout and reset if it is not receiving enough current to support 4.3 volts or higher.
If your KTunerFlash V2 is restarting itself after power on then your USB port is not delivering enough power to the unit in order to properly function.
The LCD display will power down if no ECU is detected. You're still able to complete other functions like setup LEDs, retrieve on board logs, and upload tune files to the unit.
If you have no computers that have a high power USB output it is best to connect to the device while it is powered through the OBD2 port on your vehicle.
We would rather the unit brownout as an indicator than possibly have corrupt data due to low voltage and fail an ECU flash in the field.