I was on my iPhone scrolling through a web page when it randomly shut off and came up with the boot screen. I thought it was weird, but just thought it'd reboot and all would be fine. However, it seemed that it was in a reboot loop and will not turn back on. I plugged it into the computer and still nothing. However, as I was writing this message, the phone vibrated then came back on again! At the moment everything seems fine, but could this be an indication of a bigger problem? Could something be happening to the phone? Should I start backing things up, maybe restore the firmware? It is jailbroken, but I haven't installed anything from Cydia in ages and I don't have any emulators or ROMs that have been causing trouble recently.