Found it!

M280 P64 S10
--- P64 is pin 11 SERVO (see diagram -- expansion header)

config.g

M574 Z1 S2 ; Set endstops controlled by probe
M558 P9 H15 F120 T6000 ; Set Z probe type to bltouch and the dive height + speeds
G31 P25 X-42 Y0 Z0 ; Set Z probe trigger value, offset and trigger height

Deploy.g
M280 P64 S10

Retract.g
M280 P64 S90

HomeZ.g
G91 ; relative positioning
G1 Z15 F6000 S2 ; lift Z relative to current position
G90 ; absolute positioning
G1 X200 Y200 F6000 ; go to first probe point
G30 ; home Z by probing the bed

; Uncomment the following lines to lift Z after probing
G91 ; relative positioning
G1 Z15 F6000 S2 ; lift Z relative to current position
G90 ; absolute positioning

!!!---------!!!
You don't need to cut the 3V pin on the BLTouch with the Duet 2 Maestro anymore. I did, it still works, but you don't need to for "Z_PROBE_IN". Dev said it can handle 50V.

Would be nice if the docs were kept up to date on a commercially released product.

Hi.

EDIT: ADMINISTRATOR NOTE! THIS IS THE INCORRECT WAY TO WIRE A BLTOUCH TO A DUET MAESTRO, AND MAY DAMAGE THE DUET! See: https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe#Section_Duet_2_Maestro

The documentation is lacking on BLTouch use on a Duet 2 Maestro.

Here is how I have my BLTouch wired:

I'm using Z_PROBE_IN, 2x GND 5V and trying to use the Pin 11 SERVO on the expansion header

Here is my probe config:
M574 Z1 S2 ; Set endstops controlled by probe
M558 P9 H15 F120 T6000 ; Set Z probe type to bltouch and the dive height + speeds
G31 P25 X-42 Y0 Z0 ; Set Z probe trigger value, offset and trigger height
M557 X15:368 Y15:373 S20 ; Define mesh grid

Deployprobe is:
M280 P3 S10 I1

When running M280 P3 S10 I1 --- I get
Invalid Servo Index 3

I can't find any documentation on what config or commands to use!