EMUI 12 for STK-L21 Huawei Y9 Prime 2019 is rolling out. This firmware is only suitable for devices with cust C432. You can always check the cust version in the build number of your phone. Only non-branded and open-market models are supported for this upgrade. The phone needs to be running EMUI 10 latest firmware before attempting this update. If you are living outside but your phone has cust c432 you can still install this update. Strictly not for Y9s

Changelog:

• This update introduces EMUI 12, providing you with an intuitive interface, a multi-device section in the Control Panel, and various useful functions.

Huawei Y9 Prime 2019 update Requirements:

• Disable antivirus/Windows Defender (Very Important)
• The phone must be running the latest EMUI 10
• Your phone must have cust version C432 (check build number)
• The battery must be charged up to 60%
• Good quality USB cable
• Windows 10 / 11 computer
• Hisuite 11.0.0.610 OVE must be installed Download From This LINK
• Download Hisuite Proxy V3.1.3 from THIS LINK
• Connect phone in Hisuite

Installation Process:

• Extract the Hisuite Proxy V3.X.X
• Run Hisuite proxy, and make sure you allow firewall access when it asks
• Tap on the ” Setup “ button in the Hsiuite proxy.
• Tick “Override IMEI”
• Make sure you tick in “Target build number”
• if your phone is a dual sim copy STK-L21M-LGRP10-OVS 102.0.0.225(C432E2R2P1)
• paste it in the “Target Package Build Number” section
• Must tick ” Force Auth Bridge “
• Open Hisuite again and connect your phone, check for updates in Hisuite 
• Start installation
• For your ease, please see the exemplary screenshots below

Important: If installation fails at 99%, set the date of your computer to 01-September-2023, and run the update again, it will succeed.

Watch the video for more help

Credit: Huawei Firmfinder Team

Note: Everything you do at your responsibility, this guide is provided for free without any guarantee.