The TwoTrees Sapphire Pro typically ships with an MKS Robin Nano motherboard (versions 1.1 or 1.2). Because the stock Robin firmware is somewhat closed and rigid, the community has developed several fantastic open-source alternatives.
If you cannot find a pre-compiled firmware link that matches your exact setup (e.g., dual Z, filament runout sensor, E3D hotend), you must compile Marlin yourself. two trees sapphire pro firmware link