Shader not working the same on iPhone vs PC

I've written a basic toon shader that doesn't seem to work properly on the iphone. On the PC it looks unlit, but on device it's lit. I'm assuming it's something to do with the Emission property, but I have no idea what. Can anyone spot what I've done wrong?

Code (CSharp):

1. Shader "Custom/Cartoon/Unlit"
2. {
3.     Properties {
4.         _MainTex ("Base (RGB)", 2D) = "white" {}
5.         _Color ("Color", Color) = (1.0, 1.0, 1.0, 1.0)
6.         _OutlineColor ("Outline", Color) = (1.0, 1.0, 1.0, 1.0)
7.         _Outline ("Outline width", Range (.002, 0.1)) = .005
8.     }
9.    
10.     SubShader {
11.         Tags { "RenderType"="Opaque" }
12.         LOD 200
13.         ZWrite On
14.         Cull Front
15.        
16.         CGPROGRAM
17.         #pragma surface surf Unlit vertex:vert
18.  
19.         half4 _Color;
20.         half4 _OutlineColor;
21.         half _Outline;
22.  
23.         struct Input {
24.             float2 uv_MainTex;
25.         };
26.      
27.         void vert (inout appdata_full v)
28.         {
29.             v.vertex.xyz += v.normal * _Outline;
30.         }
31.  
32.         half4 LightingUnlit(SurfaceOutput s, half3 lightDir, half atten)
33.         {
34.             s.Emission = _OutlineColor;
35.             return half4(0.0, 0.0, 0.0, 1.0);
36.         }
37.        
38.         void surf (Input IN, inout SurfaceOutput o)
39.         {
40.             o.Albedo = _OutlineColor.rgb;
41.             o.Emission = _OutlineColor.rgb;
42.             o.Alpha = 1.0;
43.         }
44.         ENDCG
45.        
46.         ZWrite On
47.         Cull Back
48.         CGPROGRAM
49.         #pragma surface surf Unlit
50.         sampler2D _MainTex;
51.         half4 _Color;
52.  
53.         struct Input {
54.             float2 uv_MainTex;
55.         };
56.  
57.         half4 LightingUnlit(SurfaceOutput s, half3 lightDir, half atten)
58.         {
59.             return half4(s.Albedo, s.Alpha);
60.         }
61.    
62.         void surf (Input IN, inout SurfaceOutput o)
63.         {
64.             half4 c = tex2D (_MainTex, IN.uv_MainTex);
65.             half4 final = saturate(c * _Color);
66.             o.Emission = half4(0.0, 0.0, 0.0, 1.0);
67.             o.Albedo = final;
68.             o.Alpha = c.a;
69.         }
70.         ENDCG
71.     }
72.     // FallBack "Diffuse"
73. }
74.