Hi, Try flashing the firmware for the BLtouch before you connect the pins to the mainboard. This helpt for me.

Well, I have to admit, 1.4.1 is not working correctly. Guess, I do not have the correct 'extensions'. However, all the bins from the zip are booting. Give it a try. One will fit your needs

@Prydonian I'm in exact same spot as you. Did you ever fix it