[Huawei Mate 20 Pro Questions & Answers] gamekill:
Background info:

My Mate 20 Pro stopped receiving updates several months ago, maybe almost one year.

I never got notifications about new updates, and searching for one was useless.

I figured I was stuck on 9.1.0.300 forever, for some reason.

Recently I finally got it "unstuck" and updated to the latest Android 10 version (as of writing) 10.0.0.206.

Here is how I did it.

DISCLAIMER: I am only describing what I did; maybe it will be useful information for someone.

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What I did, that finally worked, to update Mate 20 Pro to EMUI 10 (Android 10) from 9.1.300:

I went from 9.1.0.300 (down)-> 9.0.0.210 (up)-> 9.1.0.320 (up)-> 10.0.0.187 (up)-> 10.0.0.206

First two steps I did manually / hacked HiSuite, last two steps were official OTA through Wifi.

1 - First I downgraded from 9.1 to 9.0:

I followed this youtube video ,that is basically an explanation of this original XDA post

In the Youtube page's description there is a link to get a ZIP from Google Drive containing the older version of HiSuite, and the patcher for it.

So I downloaded and used those.

For the "update_full_base.zip" I downloaded the 9.0.0.210 from the XDA post (direct link for it here). Which is mentioned in the Youtube tutorial.

IMPORTANT!!: The install process on phone screen (progress circle) went smoothly, and the phone rebooted automatically (as expected);

BUT the boot screen Huawei logo was static, not oscillating or indicating any progress.

I waited a good 10 minutes and it did not move from that.

So I force-powered down the phone holding "vol up + power button" for several seconds;

It rebooted into a screen saying like "your files system is severely corrupted, recovering....."

Then it recovered successfully, and rebooted into a "brand new" 9.0.0.210 Android)

>I SKIPPED CHOOSING AN APN DURING ANDROID INITIAL SETUP!<

>I ALSO DID NOT CONNECT TO WIFI!<

>Skipped everything on initial setup, just to get to the home screen<

2 - Then same process all over again, with the same HiSuite and patch files, but different "update_full_base.zip", for 9.1:

I downloaded a 9.1.0.320 zip from the ONLINE FIRMWARE DATABASE https://pro-teammt.ru/en/online-firmware-database/

(for me specifically, I used LYA-L29C675E17R1P17B320 (9.1.0.320)) <- my phone is c635, this file is for c675, but I could bot find one for c635 lya-l29 9.1

DIRECT LINK TO THIS update_full_base.zip http://update.dbankcdn.com/TDS/data/files/p3/s15/G4500/g1755/v319250/f1/full//update_full_base.zip if someone does not want to or cannot use the Online Firmware Database website.

IMPORTANT!!:

At the very end of the install process on the phone screen (the progress circle), install said "FAILED!", but then when the phone rebooted it had in fact been upgraded.

I had updated to a "brand new" 9.1.0.320.

3 - Minor update to 9.1.0.362:

On the phone itself I finally connected to Wifi for the first time (STILL SKIPPED APN);

checked online for update (on Settings), found a minor update to 9.1.0.362. Installed it.

Rebooted normally into 9.1.0.362.

4 - Finally updated to Android 10:

Checked Settings for update again (Wifi was already configured/connected), 10.0.0.187 was available;

downloaded/installed it.

I got finally to Android 10 (10.0.0.187)

5 - Minor update to Android 10.0.0.206:

After installation, just a couple of seconds after the reboot of the fresh Android 10, another even newer version (10.0.0.206) pop-up showed automatically, so I installed it too.

PS: Only after having installed the latest 10.0.0.206 version and booting into it, I enabled the correct APN from phone's Settings.