RB951G-2HnD can't turn OFF LED

Dear Sirs,
I’ve tried to turn off the LEDs on this routerboard, without success.
If I set as ALL LED OFF IMMEDIATE return the could’nt change led settings erro.
I don’t want any LED ON.
Is there something special to do to make this work?
Thanks, BR

/system leds> print
Flags: X - disabled, * - default

TYPE INTERFACE LEDS

0 * off user-led
user-led
1 off
Schermata del 2017-05-01 10-44-47.png

It’s a good question, and one I’ve been meaning to ask as well.

Also, why is there a difference between the 951G and the 951Ui in terms of LED capability, given these are otherwise so similar?
On the 951Ui:

# may/01/2017 10:45:17 by RouterOS 6.38.5
# software id = XXXX-XXXX
#
/system leds
set 0 disabled=no interface=ether1-master-lan leds=led1 type=interface-status
set 1 disabled=no interface=ether2-slave-lan leds=led2 type=interface-status
set 2 disabled=no interface=ether3-slave-lan leds=led3 type=interface-status
set 3 disabled=no interface=ether4-slave-lan leds=led4 type=interface-status
set 4 disabled=no interface=ether5-slave-lan leds=led5 type=interface-status
set 5 disabled=no interface=wlan1 leds=wlan-led type=interface-status
/system leds setting
set all-leds-off=never

On the 951G:

# may/01/2017 10:48:32 by RouterOS 6.38.5
# software id = XXXX-XXXX
#
/system leds
set 0 disabled=no interface=wlan1 leds=wlan-led type=wireless-status
/system leds setting
set all-leds-off=never

Why can’t I control the ethernet port LEDs on the 951G?

What a nice surprise with the update, I can’t believe you can turn off by software the LED of a rasbperry pi and not those of the routerboar.
Black tape, will solve the problem?
Schermata del 2017-05-04 18-54-34.png

Some news in this field?