Hi Rodrig,
1 - On Apple devices is not supported to switch automatically from a cellular to wi-fi, this can be done only if you restart the app.
I will investigate anyway this thing.
2 - The default channel is saved only when you are in a public channel. We will take in consideration of adding this feature.
Thanks for the suggestions and the greetings,
walkie talkie is a remake of our CB Radio Box (landscape).
We took the suggestions of making another radio in portrait for better use when you need one hand.
If you have more suggestion for a new update, don't hesitate to notify and we will add it if will be useful.