Hold the power button to turn off, then hold power+vol down to enter recovery mode. wipe and reflash. You need to use stock kernel(no furnace either, it causes Phone FC's) for the time being. Also, you need to be on ZV8 radios, by extension.
Phone: Google Nexus 5 "hammerhead" ROM: LiquidSmooth F2FS Kernel: ElementalX 1.00
Tablet: Amazon Kindle Fire (Gen 1) "otterx" ROM: CM11-F2FS by Hashcode
Tablet: Google Nexus 10 "manta" ROM: LiquidSmooth F2FS-All Kernel: KT-Manta F2FS-All
Retired: Sprint Motorola Photon 4G "sunfire", Sprint LG G2 "LS980"