Are you looking to back to EMUI, or are you just trying to get the latest security patch ?
Works with almost all recent versions of the official Huawei HiSuite. hisuite proxy v313
The official HiSuite should now "see" the version you entered in the Proxy as an available official update. Click and wait for the download to finish. Common Troubleshooting Are you looking to back to EMUI, or
Unlike custom ROMs, this method works on locked devices. hisuite proxy v313
Check the box for if you are moving between major versions (e.g., EMUI 11 to EMUI 12).
This usually means the firmware you chose is not compatible with your device's current regional ID (Cust). Double-check that your firmware matches your region.