I ever face to your problem when I try to use dual Z independence. I found the solution as below;

Config.g
;Define Axis
M584 X0 Y1 Z2:4 U4 V2 E3

homez.g
G91 ; relative positioning
G1 V5 U5 F6000 S2 ; lift Z relative to current position
G1 S1 V-405 U-405 F1800 ; move Z down until the endstop is triggered
G92 V0 U0 Z0 ; set Z position to axis minimum (you may want to adjust this)

We need setup one more axis and home the individual driver. So it will true independence endstop one each driver.

One more, do you have another program for buy new one with exchange old defect for discount?.
Thankyou.

Thank you very much. I will contact for replace for a refurbished board.

First ,I upgrade board form X5S board and buy new wire, I forgot to checked new wire connect to step motor(I test phase form old wire) . So I conncect with new wire.. All motor was turn left and right (shaking)when I move each x y z. I try to switch wire and test on Z. Finally, I can move the motor correctly for Z and I try to connect the correct wire to x and move. Motor was shaking and show the error as above" Error: short-to-ground on drivers 0 1" . I try to switch wire agian but still turn left and right(shaking) when I move X. For Y was same too.

Hello,
I just got Duet Ether and wiring step motor on Driver 0 1 2 . I found that I wired wrong step motor , it 's shake when try to move. I try to switch wire and found the Error: short-to-ground on drivers 0 1. So I unplug all step motor and try to move x and y , the Error: short-to-ground on drivers 0 1 still appear. My driver short circuit ?

Thank.