Reproduction steps:
1. Open the attached "Blur" project.
2. Open and play the "Blur" scene.
- Note how the picture looks(Screenshot attached).
3. Build and run this scene for older GLES2.0 device(i.e. iPad 2).
- Note how the picture looks(Screenshot attached).

Actual result:
Entire camera view is very bright.

Workaround:
Open "Standard Assets > Effects > ImageEffects > Shaders > _BloomAndFlares > MobileBlur.shader" and change line 42:
From
fixed4 color = tex2D (_MainTex, i.uv20);
to
half4 color = tex2D (_MainTex, i.uv20);

Reproduced with:
5.3.6p6
5.4.1p2
5.5.0b5
iPad 2 8.1.3

Not reproducible with:
iPad Air 2 9.3.2

Solution:
Old image effects are deprecated