When trying to set the M851 Z0 the printer always says
Send: M851 Z1Recv: echo:Z Offsetz_min: -15z_max: -5

Both of -5 and -15 bang the head into the bed and i cant set it any less than that. im guessing somewhere in the firmware it was set wrong just seeing if its posible to fix it without re flashing it.
it needs to be set like -1 or even +1