I have an old Samsung Galaxy S4 (GT-I9505), Android 5.0.1, Kernel 3.4.0-5978264, which I wish to use as a PDA without phone/cell functionality. The unit is not "rooted".
The problems it is causing is general irregular behaviour, unforeseen reboots, reboot loops/hangs.
The "phone/cell" part of this unit is causing problems, and I have removed the SIM card, I have preformed a "delete cache" and "wipe data/factory reset" on the device.
This allows me to boot the device, go to airplane mode, and and by enabling this disable all networks. At this point, I am able to only enable WiFi networking, and the device is stable to use.
However, I would like to disable all Phone/Cell related software so I don't have to enable airplane mode, and further stabilize the unit. Only WiFi is the only external network protocol which I like to use. (not GSM, not 3G/4G, not bluetooth)
So my question is: how do I disable all Phone/Cell functionality ?