[Huawei Mate 9 Questions & Answers] zgfg:
In Edit 2, you put the wrong, your local link to d:\JUnk\howta8.jpg

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Some background behind the HWOTA methods.

HWOTA stands for Huawei OTA,

HWOTA(7) is for N (Android 7), HWOTA8 for O and HWOTA9 for Pie

How does stock OTA act (roughly):

- It checks if there is an update for the particular model (like Mate 9), Android version (MM, N, O, P, Q), based on the installed stock firmware.

- If the update exists (it's offer also depends on policies for the particular mobile operators), it downloades the corresponding update*.zip files (for N there used to be three files, for O two files and for P single file).

- It downloads the update*.zip files, rename (more about below) and concatenate them (>> UNIX operator) to /cache/recovery/command folder.

- It then reboots to stock recovery which finds downloaded update in that cache and checks if it is proper update based on the installed firmware, and if it was it starts 'updating'.

What are the 'problems' if user wants to mimick OTA to e.g. upgrade (when phone does not offer OTA), upgrade to a specific version or even downgrade:

- User must find himself the update*.zip files for particular firmware he wants, they can be found on e.g. that pro-teammt.ru server (link in the previous answer) - server is maintained by Firmware Finder group (but FF app does not properly link the second and third update*.zip files in case of O or P).

- Second and third update*.zip files may contain submodel info (like L09 or L29) and cust/region (like EU) in their names, if so they have to be renamed.

- User has no access to the cache, one must use TWRP or certain flashy app(s) that require root to concatenate the update * zip files there, in either case Bootloader must be unlocked (TWRP cannot be flashed and/or phone cannot be rooted without).

- Assuming that you downloaded, renamed and concatenated the update*.zip files to /cache/recovery/command folder and rebootef to recovery, stock recovery will check and recognize that you are eg skipping a version, downgrading or something and will not continue - therefore the so-called non-check recovery must be used instead, it is made from the stock recovery but the part that checks if update * zip files are correct is punctured out

Hence HWOTA methods operate the following way:

- If there is a script running from the PC side then the script flashes TWRP to the recovery, if not user has to flash TWRP himself.

- TWRP must be for the proper model (like Mate 9) and Android version (N, O or P).

- Phone must reboot to TWRP and 'installation,' of HWOTA TWRP script must be started.

- HWOTA TWRP script concatenates the prepared update * zip files to that folder in cache and it finally flashes the non-check recovery (to recovery, over the TWRP itself)

Phone then reboots to the non-check recovery, it finds update in cache, the non-check recovery skips checking and starts the installation (if update is incompatible, phone can get bricked)

Because of all that above, INF parts (update-binary file - actually a text file that can be edited by Notepad) of HWOTA TWRP scripts differ since they have to copy/concatenate one, two or three update*.zip files and the non-check recoveries that are usually named differently

But one can modify HWOTA from one model to another by replacing the non-check recovery and by modifying the INF parts of the HWOTA TWRP scripts

The only problem is to find a non-check recovery for the particular model and Android version (there was one thread on XDA about the non-check recoveries but AFAIK it was never openly published how to modify the stock recoveries, people later directly contacted the author and modified the stock recoveries for their models themselves)

Alternatively, instead of TWRP, there were also developed certain flashy or so called apps that concatenate update*.zip files (again, downloaded by user) to that cache folder, but for those app(s) phone must be rooted.

At the end, non-check recovery must be flashed and booted to, to start the 'update' (upon updating, previous root will be lost)

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Not sure now, maybe those three guys that rebranded from c567 Oreo and upgraded to c432 Pie, did not use HWOTA8 but the flashy app approach

EDIT:

DLOAD method works similarly: update*.zip files must be downloaded to /DLOAD folder on Internal memory.

Phone must be rebooted with Vol+ and Vol- being pressed - it will look if /DLOAD folder contains the update and if the update files belong to FullOTA-MF-PV.

If so, it will concatenate update*.zip files to the folder on /cache and phone will report to recovery to continue with the installation of update.

Hence for DLOAD FullOTA-MF-PV must be used but Bootloader does not need to be unlocked (no need for TWRP or the root flashy apps)

However, you don't need just to update but also first to flash c432 oeminfo - therefore you cannot avoid TWRP and unlocked Bootloader

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You could also ask for HWOTA8 for Mate 9 and for its L29c432 Oreo oeminfo file at the Telegram group:

Huawei flashing maniacs

https://t.me/flashing_huawei