// Gain current texture
Texture2D oldTexture = colorizeMaterial.mainTexture as Texture2D;
// Create new texture and copy old texture
Texture2D texture = new Texture2D( oldTexture.width, oldTexture.height, TextureFormat.ARGB32, true );
Color[] listColors = oldTexture.GetPixels( ); // <----- this one crashes
texture.SetPixels( listColors );
The previously assigned texture is flagged as readable.