iOS 9.1 draining battery on 6s

Instead of thinking about going backward, why not try to diagnose the actual problem?

I strongly suggest you check Settings > Battery and see what app(s) are using the most battery.

You can not downgrade IOS installations, whatever you actually installed will be there until the next update.

I hope this is not too difficult to understand

You're welcome.

I Actually have the same problem.

The phone is getting hot while used and the battery goes down 1% per minute (while using).

sometimes (not always) doing a hard reset of the iPhone after installing an update fixes this

It seems that signing off from iCloud stops battery drain and overheating but is not a real solution as I need iCloud sync.

Lirium Info Lite App measures about 60% CPU load *permanently* when iCloud is on. With iCloud off CPU load is is oscillating between 0 and 20%.

Same experience with iOS 9.1 and Swisscom. Starting the device but do NOT unlock the SIM card, WiFi enabled, iCloud enabled: CPU usage is normal.

As soon as you unlock the SIM CPU usage goes up to 60%.

Same story in here, iPhone 6 with Swisscom. I can see how the battery is decreasing 1% per 3 min. Even when not in use. Same settings as with 9.02, hab no probs.

I'm also on the Swisscom Network. Maybe the new Advanced Calling (WLAN Calls) activated 2 Days ago has some ******* BIG BUGS!

Funny Thing: On Battery Settings there is no change, so not 1 App which consumes like all power, even phone is constantly ******* hot! so i guess CPU Usage is the real Problem

I have solved by doing a phone restore.

Since I did not have any setting i care of and not so many application, I have even installed the iphone as new phone. This has solved the issue completely.

I have also noted that before the CPU was always at 60% and you can feel it by feeling the phone temperature.

Now the CPU use it is way lower and the temperature too.

It would be interesting to understand what was actually causing that huge CPU usage, to find a solution which does not involves the phone reset.

@Diego: since you have no issue in restoring your phone from scratch, may I ask you to do the following?

1) Check your iOS version in "Settings / General / About" --> 9.1 (13B143)

2) Check your Carrier version in "Settings / General / About" --> Swisscom 22.1

3) Activate WiFi Calling in "Settings / Phone"

4) Hard reset (press Home + Power buttons till you see the white Apple, then release)

Thank you 🙂

*edit: 5) Check the CPU again

Thanks a lot Zolpho, the problem is now back! :-)

it is definitely due to the wifi calling option (now that I remember I have received also an operator update with the 9.1!).

As soon as i have enabled this option, the cpu started again to work heavily, the phone is now hot and the battery drain fast.

I have Salt 22.1 by the way, not Swisscom.

Disabling again the feature does not help, I have tried the reset with home and power button, but no changes.

Network setting restore does not help, setting restore neater.

So I guess the only thing that works is the complete restore which I am going to do now (thanks again Zolpho :-))

So, don't enable wifi calling!

Oops

I'm sorry Diego lol

Now I have the confirmation about the issue.

So, both Swisscom and Salt, has the same problem!

Please let us know if a new restore solve the issue!

Then we have to wait for a new Carrier update 😠