Shader Doesn't Work On Android

Why doesn't this shader work on Android? I just alpha blend two textures.

 Shader "Cone/Tile" {
     Properties {
         _MainTex ("Base (RGB)", 2D) = "white" {}
         _Wallpaper ("Wallpaper", 2D) = "white" {}
     }
     
     SubShader {
         Pass {
             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
 
             #include "UnityCG.cginc"
 
             uniform sampler2D _MainTex;
             uniform sampler2D _Wallpaper;
             
             struct input
             {
                 float4 vertex : POSITION;
                 float4 tc : TEXCOORD0;
             };
             
             struct vertOut {
                 float4 pos : SV_POSITION;
                 float4 scrPos;
                 float2 tc;
             };
 
             vertOut vert(input i) {
                 vertOut o;
                 o.pos = mul (UNITY_MATRIX_MVP, i.vertex);
                 o.scrPos = ComputeScreenPos(o.pos);
                 o.tc = i.tc.xy;
                 return o;
             }
 
             fixed4 frag(vertOut i) : COLOR0 {
                 float2 wcoord = i.scrPos.xy / i.scrPos.w;
                 fixed4 tex = tex2D(_MainTex, i.tc);
                 return tex2D(_Wallpaper, wcoord) * (1 - tex.a) + tex * tex.a;
             }
 
             ENDCG
         }
     }
     
     Fallback "Unlit/Texture"
 }