I have had my iPhone 6 (7,2) jailbroken for over a year now. Currently on iOS 8.4 with Cydia 1.1.26 (en-us). Just recently it has started to "reboot" itself several times during the day. No consistency at all nor with any certain app running. I can be on a phone call and it will reboot and never drop the call. After a few seconds the call is reestablished. When I refer to "reboot" the phone goes dead and the apple boot screen appears. I've not installed anything new but have performed software updates via AppStore and Cydia. For the life of me I can't determine what is causing this to happen.