Two Trees Sapphire Pro Firmware Best Work
Klipper is currently the best firmware for the Sapphire Pro if you are willing to add a Raspberry Pi. The stock Robin Nano board is supported by Klipper, and the upgrade transforms the printer into a high-speed machine.
Klipper offloads the heavy processing to a secondary computer (like a Raspberry Pi or BigTreeTech CB1). This allows for features like Input Shaper (which eliminates ghosting at high speeds) and Pressure Advance (which perfects corners and retractions). two trees sapphire pro firmware best