That's correct. You do need to hack the firmware though to not be able to access the default dialer (which he had done). I just tried on my phone: even if I i

That's correct. You do need to hack the firmware though to not be able to access the default dialer (which he had done). I just tried on my phone: even if I install Dialer one, I can always go to all applications and run the default phone app. Without the modified firmware, he could have realized the 3rd party dialer had a bug and immediately switched to the default in seconds.