This post contains a collection of Huawei P9 Plus stock rom / firmware for all variants. To know the exact firmware that is suitable for flashing on your Huawei P9 Plus, go to Settings > About. There you will get full device information that will help choose the right firmware.
Learn http://stephaniefulke.blogspot.com /2016/08/how-to-root-huawei-p9-p9-plus-and-p9.html" target="_blank">how to root Huawei P9 Plus without stress
How to flash Huawei P9 Plus stock firmware
http://stephaniefulke.blogspot.com /2016/07/how-to-flash-huawei-updateapp-stock.html" target="_blank">Click here and follow the instructions carefully to flash your Huawei P9 Plus stock firmware package.
Download credits: Somboons, xda