Steps to reproduce:

1) Download attached project 'test_ARGBFloat_009_BugReport.zip' and open in Unity
2) Build and Run 'test_ARGBFloat' scene on a device
You will see that RenderTexture created with RenderTextureFormat.ARGBFloat will not be displayed

Expected result: RenderTexture created with RenderTextureFormat.ARGBFloat should be displayed on the screen ( check attached image 'expected.png')
Actual result: RenderTexture created with RenderTextureFormat.ARGBFloat is not displayed on the screen (check attached image 'actual.png')

Reproduced with:
5.6.0f2, 5.6.1p4, 2017.1.0b9, 2017.2.0a3

Not reproduced with:
5.5.4f1, 5.6.0f1

Regression since:
5.6.0f2

Devices under test:
Reproduced with:
Samsung SM G925F (Galaxy S6 Edge)*, OS:7.0, CPU:arm64-v8a, GPU:Mali-T760, Build:samsung/zeroltexx/zerolte:6.0.1/MMB29K/G925FXXU5DQA7:user/release-keys
Samsung SM G935F*, OS:7.0, CPU:arm64-v8a, GPU:Mali-T880, Build:samsung/hero2ltexx/hero2lte:6.0.1/MMB29K/G935FXXU1BPLB:user/release-keys

Not reproduced with:
Samsung SM G950U*, OS:7.0, CPU:arm64-v8a, GPU:Adreno (TM) 540, Build:samsung/dreamqltesq/dreamqltesq:7.0/NRD90M/G950USQU1AQC8:user/release-keys
Iphone 6 ( iOS 10.2.1)

Note that in Unity 5.6.0f1 and older releases texture is rendered on the screen but not exactly as expected(black image) due to shader failure (check attached image 'blackImage.png')

Android: tested with GLES3 and GLES2
iOS: Metal - crash on startup, GLES3 works, texture is rendered with shader failure(black image) (all versions of Unity)

RESOLUTION: The issue is caused by the devices not supporting blending on render targets with floating-point pixel format. There's nothing we can do about it. We will add a runtime warning when this unsupported operation is performed, so that there's at least a little bit of diagnostic information.