The various embodiments provide methods and systems for adjusting the thermal mitigation system of a mobile electronic device when an add-on outer casing is attached. The mobile electronic device determine whether an add-on outer case is attached to the mobile electronic device and change a thermal mitigation parameter of a thermal mitigation process implemented on the mobile electronic device in response. The determination may be via a sensor or a user input. A changed thermal mitigation parameter may be stored in memory, or input by a user or in a communication from the add-on case. The changed thermal mitigation parameter may be determined based on a particular make, model or properties of the add-on case, and/or may be obtained from a database stored in the device or accessed via a network. Removal of the case may be detected and the thermal mitigation parameter returned to an initial value.