[Huawei P9 Guides, News, & Discussion] windyhawk:
It took me 2 full days to finally successfully upgraded my ancient firmware (L09C16B170) to the updated version (L09C432B397). There are a lot pieces of information that I gathered from this forum and all over the internet that collectively helped me navigate this ordeal. Just want to share it with anyone who is in the same boat, although I know that P9 won't last for too long since P10 has been out for a while. However, if you still want to revive your P9, keep reading.

Requirement

Before reading, you need to understand ways of entering different modes of your P9 phone, which will be used many many times during your upgrade:

Enter recovery mode (also how you enter TWRP) - see this GUIDE

Enter fastboot mode - see this GUIDE

Enter manual upgrade mode (also called dload method; This is NOT TWRP method) - see this GUIDE. Please IGNORE any software or download information in this guide. I want you to refer to this guide for how to do it, NOT what to use or download!

You also need to download and know how to use ADB tool which is quite simple. Search the forum or google and you will find plenty of information and the download links. If you hate command lines, you can even use the GUI version from here.

You will probably also need to use Firmware Finder for Huawei (HWFF) to download firmware of interest for manual update during this process. HWFF is an app that can be installed for free via your phone Google Play Store. The downloaded firmware is saved under the HWFF folder in the internal memory. You might need to unzip these files for upgrade via dload method or directly via TWRP method without unzipping. However TWRP method requires you to unlock the bootloader and install TWRP in the phone (see below for details).

First step - debranding

If you are already on C432xxxx, you might just skip this step. I followed this thread partially (Debranding Guide by Z-Blade), since the whole thing doesn't work for me 100%.

Z-Blade did a fantastic job describing how to debrand his C34 firmware to C342B361. My original version is C16B170 which is a South Africa branded firmware. But I found certain steps in this guide could be omitted and certain steps didn't work in my case. Here is my modified version based on Z-Blade's version:

1. Unlock your bootloader and install TWRP

How to unlock bootloader? Follow this GUIDE. Even though it's for Huawei Ascend XT. It works for P9 as well. You only need to complete Part 1.

After you unlock the bootloader, install TWRP. Depending on which firmware version you're on, the version of TWRP that might work for your device changes. I encountered numerous booting loops due to incorrect version of TWRP. Finally I found that these three versions work for me (3.1.0-0, 3.1.1-0, 3.1.1-1). Always go with the highest version first (3.1.1-1). If you find yourself stuck in the booting screen, long press your power button until you get out of it and install another version of TWRP. Please go to TWRP official website to download TWRP for Huawei P9. Follow this GUIDE to install TWRP recovery on your phone.

2. Flash OEM info file for C432

After you unlock the bootloader and install TWRP recovery, download oeminfo-huawei-p9-eval09-c432.zip from this THREAD and flash it via

TWRP method

.

3. Flash C432B136 firmware

Download and flash the dload-huawei-p9-eval09-eva-b136.zip via

dload method

from this thread. After flashing and rebooting your phone, you should be on the L09C432B136 firmware. NOTE: If it boots up to a white screen asking you to enter password, reboot into recovery by holding volume up when you powering up your phone, do a wipe partition and factory reset. You may need to reboot your phone a number times before the phone boots up correctly.

Up to this stage, you have debranded your phone to an european version.

Second step - stepwise firmware upgrade

1. Update from B136 to B166 or B182

As mentioned in Z-Blade's original post, many people will not be able to directly update from B136 to B182. I am one of them. Go into the updater in the phone setting, refresh "check for update". If you can receive B182 update, by all means go for it. If you only receive B166 update, go for it as well. After B166 update and rebooting your phone, check updater again to see if you receive B182 update in the Settings menu. If this method does not work, manually update to B182 by following the steps here via dload method.

2. Update firmware from B182 to B360/361/378 and also upgrade OS from Android 6.0/EMUI 4.1.x to Android 7.0/EMUI 5.0

According to Z-Blade, "After your phone has rebooted and you are on the B182 firmware, you need to now update the firmware to B361 via Huawei Updater 2.0". However, in my case, I tried many times and always failed at this step. I found a workaround by updating to B360 instead of B361. Please follow this GUIDE to update to B360 or B361, whichever works for you. However, please pay attention to following change that I found critical:

- The version of Huawei HiSuite is critical for the success in this step. The GUIDE provided Hisuite download link (version 5.0.0.301_OVE). However, it does not work together with Huawei Updater 2.0 in my hands. This error has wasted me almost half day. Instead, I finally found out the problem and went to HERE to download the version 5.0.1.300 and it finally worked

- However, if even after HiSuite and Updater both work together fine the update does not proceed successfully (the updater might get stuck), you need to update it manually via dload method. Search EVA-L09C432B360 or EVA-L09C432B361 in Firmware Finder for Huawei as mentioned above and download the Full-OTA version (~2G). After download, move the corresponding folder containing firmware zip files under "HWFF" folder in the internal memory to the external SD card. Unzip the firmware file and update your phone using dload method. You may also try TWRP method which can install zip files directly, but at this point, you bootloader will be re-locked and TWRP will be gone. You need to unlock the bootloader and re-install TWRP again as mentioned above.

After you successfully update the firmware to B360 or B361, now you should have Android 7.0 and EMUI 5.0 on your phone. Now go to the updater in your phone setting. You should receive B378 OTA update. Proceed with the update...

You might not need to strictly follow following steps to update your phone to any firmware beyond B378. However, since a lot of new ROMs are based on B380+ or even B390+, if you want to use those, you might need to further update your firmware first.

2. Update firmware from B378 to B383

After updating to B378 and rebooting your phone, check if your phone receives B383 update OTA. If yes, proceed. If not, go to HWFF, download B383 Full-OTA firmware and update via either dload or TWRP method.

3. Update firmware from B383 to whatever later version

After successfully updating your phone to B383, you basically can flash your phone with anything firmware and ROMs built on B380+. I find it unnecessary to update to B386. What I did was that I directly updated from B383 to B394 by following this GUIDE. Since I wanted to try BlueWei 5.7 which is based off B397, I also followed the same guide to update my firmware to B397 before flashing BlueWei ROM.

Now please enjoy all kinds of new ROMs and the fast, revived P9. After this update, my P9 is super smooth (the original firmware and OS was utterly slow and sluggish) and I think I will keep using this phone until it really can't keep up with the hardware requirement of new apps etc. :D

Hope my guide is helpful!