Official Sites/Stores:
Affiliates:
Stock EMUI (Emotion UI) has become sluggish, bloated, and outdated. If you are still holding onto this device, you have likely noticed the lag, the lack of security patches, and the absence of Android 11 or higher.
Depending on whether you want stability or the latest features, here are the most popular choices:
Always verify the STK codename. Do not flash "STK-L22" ROMs on "STK-L21" variants unless the developer explicitly says they are unified. Check the Huawei Y9 Prime 2019 (Stark) section on XDA Developers.
Without an unlocked bootloader, you cannot flash TWRP, Magisk, or any custom ROM. For years, the Y9 Prime was a modding desert.