Im wearing a MiBand. It is a BLE device and you cant pair it in android. Since the nightlie of 01-10-2016 (german 10.01.2016) MiBand dosen pair or cant be read out. Something is wrong there and there is a issue open. The workaround i found in the comments of the issue are working and is described her (german) and here (english). Links to the older files can be found in the links. Very heavy important is that you copy via recovery (TWRP) and not from inside android (some explorers with root-access)
Update: Problem is solved since Nightlys of 01-20. Thanks to CM