[Huawei P9 ROMs, Kernels, Recoveries, & Other Devel] Tecalote:
Updating EVA-L09c432b395 to b397 (not for L19 at the moment)

Okay -

1) Enable Developer Options (settings /about phone/ 7x klick on build number) - in developer options enable

a) OEM Unlock

b) ADB Debugging in charging mode

c) USB Debugging (in this order - not USB Debugging before ADB Debugging)

2) If your Bootloader is closed - you must Unlock Bootloader now

Connect P9 with USB to your PC and run Minimal ADB and Fastboot in administrative mode, with code: adb devices accept the RSA Request on Display of your P9 and set it to "yes, always from this pc and ok" - reboot your Phone into Fastboot mode and with code: adb reboot bootloader

FRP Unlock should be shown in red color, if Phone unlocked in red color you can flash TWRP, if Phone locked in green color - you must flash Bootloader Unlock with code:

fastboot oem unlock yourcode..xxx

After P9 makes Factoryreset. The lowlewel wipe is important, if it does not work to 100%, do it manually from settings / advanced settings /backup restore/ Factoryreset with Wipe of internal storage...

After Factoryreset you have to enable again step 1 Developer Options.... Then boot again into Fastboot Mode and flash TWRP: code:

fastboot flash recovery twrp-3.1.1-1-eva.img

TWRP from here: https://github.com/OpenKirin/android_device_huawei_eva/releases/download/3.1.1-1/twrp-3.1.1-1-eva.img

3) Disconnect USB from P9 soon TWRP is successful flashed and press VOL+ and Powerbutton on P9 until TWRP is booted, then allow system modification and set up your time zone, language etc...

4) Download HWOTA.zip (for L09 b397) from here: https://www.androidfilehost.com/?fid=746010030569949856

5) Unzipp hwota.zip on your PC and you should have then the unzipped folder HWOTA (it contains some files and folder, dont touch them) - copy this unzipped folder to the main directory of your external SD (no subfolders between) the path is then "NAME-OFSD"/HWOTA

6) Boot to TWRP and choose storage "Micro SD" and navigate to the HWOTA folder - inside you find the one zip with the name: hwota_update.zip - flash (only)this zip

7) Your Phone reboots now and EMUI Software Installing begin - your Phone will be updated to b397, wait until Update is finished to 100%, it will restart after by itself

8) You are now on b397

9) Bootloader is maybe closed again - than you have to do step 1 - 3 again

10) After unlock and enabled developer options and flashed TWRP - you can root your Phone - if you want to Root with SuperSU

11) Download SuperSU 2.82 SR5 for EMUI 5.0.1: https://www.androidfilehost.com/?fid=673956719939815322

Make Backup with TWRP to external SD from boot, data, system, and vendor - before Root!

If something is going wrong you can restore..

12) Flash it with TWRP and dont wipe Dalvik/Cache - Phone reboots, first reboot will be canceld, Phone reboots again, wait until it is booted to system. You have now Root with SuperSU.

13) Its recommended for full root permission to flash Busybox after - you can choose one of those two:

a) Busybox-1.28.0-YDS-UNIVERSAL.zip: https://github.com/yashdsaraf/bb-bot/releases/download/v1.28.0-YDS-201801031253/Busybox-1.28.0-YDS-UNIVERSAL.zip

or b) Busybox 1.27.2 by osmosis: https://xdaforums.com/attachment.php?attachmentid=4311160&d=1508717911

14) Done, tell me the result :)