The factory-installed motherboard will be equipped with firmware for testing (Ender3 models), which can be used directly or as needed.
BTT SKR MINI E3 V1.2 motherboard is a ultra-quiet, low-power,
high-quality 3D printing machine control board. It is launched by the
3D printing team of Shenzhen BigTree technology co., LTD. This
board is specially tailored for Ender 3 printer, perfectly replacing the
original Ender3 printer motherboard.