How hard would be to add a GSM module to this device? I assume that it won't be ...

		butz 3 days ago \| parent \| context \| favorite \| on: A Simple open-source Phone programmable with Ardui... How hard would be to add a GSM module to this device? I assume that it won't be no longer fully open source due to proprietary firmware, but that would add a whole new dimension of usefulness.