Sometimes when the firmware is corrupted or there is a fault with the circuit board, the FlexPendant gets stuck at the booting screen with no graphic or control but just a black screen. Before sending the FlexPendant to repair or purchasing a new one, one can try to force the FlexPendant to download and install the firmware again.
Use the stylus to press and hold the reset button in the back of the FlexPendant for more than 3 seconds until the screen becomes white.
Once the screen turns white, press and hold the programmable button 1 and the stop button for 10 seconds until the firmware update screen is shown, it is crucial to avoid any movement on the joystick as this can modify the calibration of the unit.
Once this buttons are pressed the firmware will reinstall, follow the instructions on the screen to finish the process.