LED Matrix not working

[hifiberry]

I can't get the LED matrix writer to work with my Nuimo. Also the dots.py demo code isn't displaying anything

After debugging the Nuimo code, I found that _matrix_writer.led_matrix_characteristic is None

In the code I see this: self._matrix_writer.led_matrix_characteristic = next(( characteristic for characteristic in nuimo_service.characteristics if characteristic.uuid == self.LED_MATRIX_CHARACTERISTIC_UUID), None) # TODO: Fallback to legacy led matrix service # This is needed for older Nuimo firmware were the LED characteristic was a separate service)

I've updated the firmware with the iPhone app, but it doesn't change anything. Is it possible that the firmware is still old even after I updated it with the iPhone app?