All smart devices, from cars to IoT, are based around processors. Often these processors are not considered as part of the threat model when designing a product. Instead, there is an implicit trust that they just work and that the security features in the datasheet do what they say. This is especially problematic when the processors are used for security products, such as bitcoin wallets, cars, or authentication tokens. In this presentation we will look at using fault injection attacks to break some of the most popular IoT processors – using less than $100 USD of equipment.