Bluetooth drivers in both ios and android never work right. You might get random undocumented error codes on some devices. Some of your connection/transmit functions will just get lost never activating a callback so every single thing needs a timeout handler. I've seen on older androids a callback inexplicably starts getting called twice in a row. I've seen the bluetooth object suddenly is null so you get a hard crash next time something tries to use it. These smartphone drivers fail in every way imaginable and in ways you can't imagine. Be impressed when a bluetooth app works reliably.