This is the stock Android 4.4.2 firmware KitKat C900B147 for European Honor 6 Plus (Pine-TL10). You can use this firmware for your device downgrade Lollipop to KitKat as you wish.
This site is not responsible for any damage that will happen to your device when flashing this honor 6 plus stock firmware.
Honor 6 Firmware Details
Device: Huawei Honor 6 Plus
Android: Version 4.4.2 KitKat
Build number: V100R001C900B147
Status: Official (stable)
Type: Full firmware image
Release Date: 01/05/2016
Download Link: Official Mirror | Size: 1.08 GB
How To Install The Huawei Honor 6 Plus Kitkat Firmware
After downloading the firmware from the link above, extract the download folder from it.
Move the downloaded folder to the top (main) directory of the phone microSD card.
Disconnect your device from the PC after that open Settings> Updates> Menu> Local Update.
Select the full Update.app package from the list and install it.
The phone will now reboot. It takes about five minutes to complete the installation.