Change alpha in runtime of gameObject with mobile shader

So I have any GameObject with assigned mobile shader with transparency support.

I need to do sth like:

void SetAlpha(float a)
    var oldCol = _renderer.material.color;
    _renderer.material.color = new Color(oldCol.r, oldCol.g, oldCol.b, a);

to make gameObject semi-transparent. But exactly for mobile shader.
But mobile shaders have noColor param =(

Material doesn’t have a color property

error is shown

That’s the point of the mobile shaders. They don’t have the color property which most shaders usually have to avoid the overhead since it isn’t required in most cases. If you need it, just use the normal transparent shader.