MobileHDR is expensive for some devices :
Is there any way to disable it in game? Or restart game?
The config is r.MobileHDR=False (or True).
And the console command would be the same.
So try Packaging a Develop build, ensure you have the console option ticked (4 finger touch), bring up the console and give it a try.
It’ll either be r.MobileHDR True (or False)
Or r.MobileHDR 1 (or 0)
Once you know it can turn on/off, at run-time and not require a device restart (it shouldn’t, as most config options can be adjusted live), then there are ways of changing configs live, without the console, as the console is stripped in Shipping builds.
In this case, the Game User Settings might be of use: Game User Settings Docs, Game User Settings Wiki
Thanks for your answer,but it doesn’t work for me,
r.MobileHDR does no thing when i execute it in game .
Are you just typing r.MobileHDR?
Or “r.MobileHDR 1” for on, or “r.MobileHDR 0” for off?
I’m going to guess you are, which would lead me to think that this is something that might require a restart 
With the Game User Settings, you change the values, then have to apply them… might be worth looking to see if there’s a way of getting/setting the particular Game/Engine config that houses MobileHDR (I think it’s in Engine.ini or DefaultEngine.ini).