This paper explores the possibility of using a genetic algorithm to launch a Spectre attack on different branch predictors with the same binary. We focus on RISC-V architectures, specifically Sonic-BOOM, as they are the most likely to have a wide variety of branch predictors while sharing the same ISA. We show that our genetic algorithm is able to find a training and attack sequence to mount a Spectre Bounds Check Bypass attack on multiple branch predictors.