Android 5.1.1 bug - back button randomly looping some apps

[vitcp]

Hi,

I have T2 Ultra Single D5303.

Recently I updated to 5.1.1 firmware (19.4.A.0.182).

But then I experience this problem.

When the phone is locked for some times and then I unlock the phone, suddenly an app is opened.

When I press the back button, it doesn't exit the app, but it shows another random app.

When I press the back button again, it opens another random app, and it continuously cycling throgh the apps.

When that happen, I will never get to the home screen unless by pressing the home button.

I notice that the apps which randomly show up, were the ones opened before the phone was locked.

The above problem will not happen if before locking the phone, I manually close all running apps first.

But I don't want to alwasy do this manually.

I've tried to clean install the firmware using Sony PC Companions.

It still randomly appear.

But the frequency is dropping ... or it just my feeling... not sure.

The problem never show up on 5.0 firmware, but ever show up on 4.0 and older firmwares.

Other than that, the 5.1.1 firmware is good and fast.

It is dissappointing that such annoying problem existed.

Does anyone has the same problem?

I hope Sony will fix the problem.

Thanks.

[Thommo]

Try safe mode and if the same happens and a system repair doesn't or hasn't helped then contact Xperia care but if safe mode does work then you have an app or apps causing this issue - http://www.sonymobile.com/global-en/support/contact-us/

[_alexdon_]

This has been reported in the past:

/t5/Xperia-Z3/Pressing-quot-Back-quot-soft-button-rapidly/m-p/987191#M16723

I have escalated this to Sony support but not sure if anything can be done about it.

[_alexdon_]

@vitcp one question. Are you spamming the back button when this problem occurs?

[vitcp]

@alexdon:

no, i press the back button normally.

even in slow motion .. heheh ...

[_alexdon_]

One suggestion: boot in safe mode and see if this still occurs.

[vitcp]

Tried safe mode for 1 hour only, problem didn't appear.

If the cause is certain 3rd party apps, it is odd because the very same apps are also installed to my other smartphone, and no problem at all.

Furthermore, running pre-installed apps like Camera also triggers the problem.

In the mean time, manually closing the apps seems to be the solution.

If there is root methods available for this firmware, I'll root my phone to run powerful task killer such as Purify or Greenify.

This will surely be the solution for rooted phone.

Thanks

[_alexdon_]

Strange, you should keep us updated.

[vitcp]

Hi,

I think I've found the solution!

Recently tried to flash the 5.1.1 firmware with Flashtool, and has been using my smartphone for the whole day without any problem.

The very same apps are also installed and running smoothly.

Previously I flashed the firmware with Sony PC Companion, either with normal (update) mode or repair mode, but both of them didn't work.

I can see big difference too with my internal storage space.

When using Sony PCC, I got around 1.5 GB free space.

With Flashtool, I got 2.1 GB free space.

It seems that the problem is with Sony PCC software (I'm using ver 2.10.281, update engine ver 2.15.13.201509231442).

Sony PCC software flashed not as clean as Flashtool.

I'm happy that my phone is running smoothly now.

Thanks.