[P8lite General] daviddosa:
As i wrote earlier in this topic, updating to Android 6.0 results you not being able to add your Google Account.

To resolve this problem, you need to carefully follow these instructions:

After updating to Marshmallow, you have to install TWRP Recovery via Fastboot. Procedure can be read below.

If it's installed, create a nandroid backup with it to you external SD Card.

Please do not jump over this step, because if anything goes wrong, the easiest way to get it working again, is with using this backup.

When the backup is completed, you should download a OpenGapps package from HERE. Select ARM64, Android 6.0, and Micro package and copy the package onto your SD Card.

You need to download THIS SuperSU v2.62-3 package as well, and copy this next to the OpenGapps package.

If both packages are present on the SD Card, you can proceed to the next step: Boot into TWRP, and flash the OpenGapps package.

It'll say the installer found some already installed Gapps, but you can ignore it. After the flashing is completed, you need to do a Factory Reset in TWRP, otherwise the phone will not launch any app.

When the Factory Reset is complete, reboot the phone normally. You should skip every setting you can skip. Wait until it completely booted up, then go into TWRP again.

For the last step, you just need to flash the SuperSU v2.62-3 package.

If you done flashing, just restart the phone in normal mode. My phone restarted itself twice without booting into the system, but after that everything was okay.

You should set up your phone now.

As sokkoban pointed out, the root gets reset after rebooting the phone, but with these settings in the SuperSU application, I managed to keep the root even after rebooting.

Enable Superuser: checked

Re-authentication: checked

Default access: [Grant]

Show notifications: unchecked

Logging: [Access only]

Clear logs after: [3 days]

Log date format: [31/12 23:59]

Auto-refresh apps and logs tab: checked

Enable su during boot: checked

Mount namespace separation: checked

Enable multi-user: unchecked

Tapjacking protection: checked

Trust system user: checked

Flashing TWRP:

Download Minimal ADB and Fastboot from HERE and install it with default settings.

Download TWRP (TWRP_2.8.7.x_P8Lite_kirin_v2.img) from HERE and copy the file into the Minimal ADB and Fastboot folder you just installed (C:\Program Files (x86)\Minimal ADB and Fastboot).

In your phone, go to Settings > About phone and tap on the Build number 7 times to enable Developer options.

Go back, enter Developer options and enable USB debugging.

Now connect your phone to your PC with an USB cable.

Shift + Rightclick in the Minimal ADB and Fastboot folder, click Open command promt here and type adb devices.

Grant access on your phone to ADB and reboot into fastboot mode by typing adb reboot bootloader.

If the phone booted into fastboot, you just need to verify the connection by typing fastboot devices.

If the phone present, type fastboot flash recovery TWRP_2.8.7.x_P8Lite_kirin_v2.img (if you only type one T letter, and press TAB, it should automatically complete the filename)

Disconnect the USB cable, and press Power + Vol Up until it boots into TWRP.

---------- Post added at 12:06 ---------- Previous post was at 11:48 ----------

I was able to use this function as well with my previous phone, but not with this one. The phone doesn't have a gyroscope sadly.