I'm going to try to keep this short and to the point. I'm not having an issue, just looking for input to help me get the most out of the configuration I setup.
I have a Pioneer Appradio 3 in my car that does not have the ability to read directly from a usb flash drive, where I hold all of my music. Instead the music resides on my HTC One, with 32gb of storage. I have well over 32gb so to make this work I created a small box with a Raspberry Pi that acts as a ad-hoc network and shares any usb hdd or thumb drive i plug into it. I then mount the network share on the HTC One to the USB folder on the phone so that music apps see it as a attached storage device. This works beautifully.
However, in the process of doing this I lose data on my phone because it is connected to a wifi network with no data, i.e. the Raspberry Pi. Is there a way to keep mobile data while connected to a network with no data? I know this is physically possible because the wifi radio stays active with data when creating a hotspot....which was the original way I was accomplishing this. However, this is no longer an option because I am using miracast to communicate with the app radio over HDMI.
For anyone that is interested the Raspberry Pi is being controlled by a simple relay and USB power source.