Material that only recieve shadows but doesn´t render (mobile)

Well, I´ve look into the internet a lot, but wasn´t able to find this for Unity 5, mobile.

This is what I need:
I want the ground plane not to render, BUT I do need to render the shadows.
The reason for this is that I´m doing a 2.5 game, i.e. the background is 2D but the character is 3D, so I only want to render the character and the shadow, but leave the floor out, since it will come from a 2D texture.
Every 3D renderer has this feature, but can´t find it in unity.
I´ve seen a material made by someone, but Unity 5 doesn´t read it.

This is what the old material used to do:

This was the code. My knolowedge of code is pretty short, so I couldn´t wrap my head around it to make it work:

[LIST=1]
[*]Shader "FX/Matte Shadow" {
[*]Properties {
[*]    _Color ("Shadow Color", Color) = (1,1,1,1)
[*]    _ShadowInt ("Shadow Intensity", Range(0,1)) = 1.0
[*]    _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
[*]}
[*]

[*]

[*]SubShader {
[*]    Tags {
[*]        "Queue"="AlphaTest"
[*]        "IgnoreProjector"="True"
[*]        "RenderType"="TransparentCutout"
[*]    }
[*]    LOD 200
[*]    ZWrite off
[*]    Blend zero SrcColor
[*]

[*]CGPROGRAM
[*]#pragma surface surf ShadowOnly alphatest:_Cutoff
[*]

[*]fixed4 _Color;
[*]float _ShadowInt;
[*]

[*]struct Input {
[*]    float2 uv_MainTex;
[*]};
[*]

[*]inline fixed4 LightingShadowOnly (SurfaceOutput s, fixed3 lightDir, fixed atten)
[*]{
[*]    fixed4 c;
[*]    c.rgb = lerp(s.Albedo, float3(1.0,1.0,1.0), atten);
[*]    c.a = 1.0-atten;
[*]    return c;
[*]}
[*]

[*]

[*]void surf (Input IN, inout SurfaceOutput o) {
[*]    o.Albedo = lerp(float3(1.0,1.0,1.0), _Color.rgb, _ShadowInt);
[*]    o.Alpha = 1.0;
[*]}
[*]ENDCG
[*]}
[*]

[*]Fallback "Transparent/Cutout/VertexLit"
[*]}
[*]
[/LIST]

Can you elaborate what exactly the problem is with this shader? Doesn’t it work with mobile? Or that it doesn’t play nice with deferred lighting? I tried it quickly and it worked (in Editor…don’t have a mobile project here to test it on mobile)

Also, please format your code. Thank you.

Well, they say -in the forum where I took it from- that it doesn´t work with mobile. I wasn´t able to run it. Maybe I did something wrong, are you positive it works in unity 5?
But yeah, the problem is that it doesn´t work with mobile, I just add that for reference.