Research from PacketSled and Patrick Kelley, CISSP, CEH, MCP at Critical Assets proves it possible to remotely brick iDevices over-the-air. The team built the exploit based on Zach Straley’s research which exposed a flaw in iOS when a user to manually set the date of an iPhone or iPad to January. 1, 1970.
Using a custom Raspberry Pi setup built by Kelley, a wifi access point resembling a commonly trusted network spoofs Apple’s NTP servers to pass the 1/1/1970 date to the device. This starts a chain reaction of software instability resulting in a observed temperatures up to 54°C… which is hot enough to brick a device.

The rPi that killed the iPad
The team reported the exploit to Apple who released the update 9.3.1 to address the issue.
Read more on Krebs: krebsonsecurity.com