OreSat is an open source, modular CubeSat developed by Portland State Aerospace Society (PSAS) at Portland State University. OreSat uses Gallium Arsenide solar cells with a firmware-implemented maximum power point tracking (MPPT) algorithm. During testing, we found serious performance issues in the firmware while using our hardware-in-the-loop simulation infrastructure. Specifically, power generated collapses on decreasing solar intensity, leading to a power brown out. Successive brown outs contribute to a very high amount of off-time, leaving lots of potential power unharvested. My project was to fix these issues in firmware. The challenge is that our solar modules can only control the current out of the cells (as opposed to voltage control). This is theoretically more efficient, but it forces the MPPT algorithm to work in the current domain, which is unstable, as drawing too much current can cause power output to plummet. This is made worse by quickly changing intensities, which can turn an ideal current into one that causes a brown out. Traditional algorithms (perturb and observe) that hone in on the MPP itself are unreliable here because the MPP is so close to the power cliff. In order to increase reliability, the firmware was changed to consider the estimated current-power curve, which is a reliable proxy for intensity. This approach resulted in near ideal tracking ability and a high resilience to changes in intensity without crashing. These changes, in addition to applying best practices, have left the firmware more efficient, effective, and maintainable.