Turn off your hp first before putting it inside the freezer. once the hp become at least less than 10°c you can try to turn on you hp.
same issue here...i put my find 7 in the freezer...then the display come out again...try it out. but make sure wrap your phone with a plastic bag first... black screen again everytime i restart my hp. have to put it in the freezer again.
Last edited by cgfusion; 26th May 2015 at 12:08 PM.
Reason: adding detail.