Step 6 – Once you are in TWRP Recovery, perform a full data wipe by tapping on the ‘Wipe’ button. Then swipe on the “Swipe to Factory Reset” option at the bottom.
Step 8 – Confirm installation on the next screen by swiping on the “Swipe to Confirm Flash” option. The installation procedure should start now as show below.
Step 11 – You can now reboot your phone by selecting the “Reboot System” button.
Your Huawei P9 will boot now and it might take about 5 minutes to boot on your first time after flashing a new ROM. So, please wait.
That’s it! Your Huawei P9 should now have Android 7.1 LineageOS Nougat custom ROM installed! Go to Settings > About phone to verify.
If you run into any problems, feel free to drop us a comment below and we will reply you back ASAP with the fix or the solution to your problem.