How to enable third button cheat in final fight Mame?

In Mame we have a third button that simulates pressing punch and jump at the same time

However, it doesn't work at all. I mean I press Joy 1 Button 2 and it doesn't work. Perhaps because it's a cheat. Should I do something to the machine to enable it?

Also I put nothing for P1 button 1 that's because I need autofire.

This is the content of ffight.cfg

<?xml version="1.0"?>
<!-- This file is autogenerated; comments and unknown tags will be stripped -->
<mameconfig version="10">
    <system name="ffight">
        <counters>
            <coins index="0" number="7" />
        </counters>
        <input>
            <port tag=":IN1" type="P1_JOYSTICK_RIGHT" mask="1" defvalue="1">
                <newseq type="standard">
                    JOYCODE_1_HATSWITCHR
                </newseq>
            </port>
            <port tag=":IN1" type="P1_JOYSTICK_LEFT" mask="2" defvalue="2">
                <newseq type="standard">
                    JOYCODE_1_HATSWITCHL
                </newseq>
            </port>
            <port tag=":IN1" type="P1_JOYSTICK_DOWN" mask="4" defvalue="4">
                <newseq type="standard">
                    JOYCODE_1_HATSWITCHD
                </newseq>
            </port>
            <port tag=":IN1" type="P1_JOYSTICK_UP" mask="8" defvalue="8">
                <newseq type="standard">
                    JOYCODE_1_HATSWITCHU
                </newseq>
            </port>
            <port tag=":IN1" type="P1_BUTTON1" mask="16" defvalue="16">
                <newseq type="standard">
                    NONE
                </newseq>
            </port>
            <port tag=":IN1" type="P1_BUTTON2" mask="32" defvalue="32">
                <newseq type="standard">
                    JOYCODE_1_BUTTON2
                </newseq>
            </port>
            <port tag=":IN1" type="P1_BUTTON3" mask="64" defvalue="64">
                <newseq type="standard">
                    JOYCODE_1_BUTTON3
                </newseq>
            </port>
        </input>
    </system>
</mameconfig>

I do not see anything that enables that third button either

mame final-fight

Best Answer

According to https://kb.speeddemosarchive.com/Final_Fight/Basics

A short note on button 3. Anyone who has played Final Fight in mame may have taken notice that button 3 can be bound, and appears to do nothing. This seems to be a leftover development button, and it still has one function. Specifically, pressing button 3 when being grabbed (primarily by Andores or Abigail), will result in your character falling out of the grab. No official documentation contains any references to button 3, it is not an available button on any official cabinet, does not show up in the input check, and it is not included in any port of the game, so use of button 3 is regarded as a cheat by SDA standards.