Problems with ios 8 and iphone 5s?

Question

iPhone

I updated IOS to 8.1.1, the phone began to slow down.
1. Began to think for a very long time after you go to the multitasking panel. After about half a second / second, it begins to perceive a touch on the screen. The same is true when exiting folders.
2. How to disable the health app? I do not need it, but it eats a battery.
Jail is not installed, effects are disabled.
upd:
I'm sorry. Forgot to mention:
1. On 8.1 the same problem.
2. I tried to restore iphone with clean firmware to both 8.1.1 and 8.1.

Answer 1

Downgrade from 8.1.1 to 8.1 I don’t know if it’s possible to post links to third-party sites, you can find it on the first links in Google. Downgrade can always be done only on the previous version.