Body Biasing Injection (BBI) is a fault injection method involving applying a voltage pulse onto the backside substrate of integrated circuits using a conductive needle. Some studies have been focusing on the characterization of BBI effects, but no fault model explaining the origin of the induced faults has yet been established. The repeatability of this method has been demonstrated, and electrical models have been proposed. However, up to the best of our knowledge, no successful differential fault attack using BBI and single bit fault model on hardware coprocessors has yet been reported in the literature. Within this context, this work presents enhanced practices to perform BBI in an even more reproducible and reliable way compared to previous works. It also brings insights on how and why faults occur under BBI and presents a fault attack performed on a hardware AES coprocessor embedded in a modern 32-bits microcontroller.