Recently, different software and hardware based checkpointing strategies have been proposed to ensure forward progress toward execution for energy harvesting IoT devices. In this work, inspired by the idea used in dynamic compilers, we propose SFSG: a dynamic strategy, which shifts checkpoint placement and specialization to the runtime and takes decisions based on the past power failures and execution paths taken before each power failure. The goal of SFSG is to provide forward progress and to avoid facing non-termination without using hardware features or programmer intervention. We evaluate SFSG on a TI MSP430 device, with different types of benchmarks as well as different uninterrupted intervals, and we evaluate it in terms of the number of checkpoints and its runtime overhead.