The light above the camera is nearly always on with the cover closed, is this telling me something?
The last time I saw this light for any significant length of time was when I visited a friend who is on the very edge of cellular civilization. My phone would get a very poor 3G signal or even just what it called "G" or no signal at all.
At those times my light varied between red and purple. I think the purpose of this light is to let you know of degraded cellular performance.
I do occasionally see a red light right after a call. I think this is because the phone drops to 3G for the duration of the call and the status light is slow to reflect that 4G is restored when the call ends.
Opening the case immediately clears the red light in those cases.
