TC55 Volume

TC55 / Stage Now - Volume control - I'm trying to disable the option to put a TC55 in to vibrate / silent using stage now.

I've followed instructions here https://techdocs.zebra.com/emdk-for-android/6-9/mx/audiomgr/
I've set the mute/vibrate state to "unMute - Turn on audible sounds". This does not disable the option of muting the device.

As an aside - Anyone know what an occasional red flashing light means on a TC55 when on charge. So flashing green.. and then occasionally red.

Look forward to hearing from any wise users.

James