Toggling Unity iOS OpenGL ES 1.1/2.0 Settings

While trying to learn Cg using Unity's ShaderLab to preview, I found that if my player settings is configured to target "OpenGL ES1.1", my custom vertex shader doesn't work and the victim cube becomes all black (probably a result of falling back to VertexLit?).

It makes perfect sense to not execute my program because the shader is compiled to be fixed-function for OpenGL ES 1.1, but after I realized the fact, I toggled the settings to target "OpenGL ES1.1+2.0": the result doesn't change at all, until I quit and restart Unity to reload the project.

This behavior with no warning and no errors is quite confusing in my point of view. I tried reimport the shader but it'd remain fixed-function.

My question is: am I missing some steps to force update the settings? I'm using Unity 3.4.1.