If you ever get an error like "secure boot fail" or "BROM error: S_FT_ENABLE_DRAM_FAIL" after flashing your Huawei Y6II LYO-L02 mobile, then understand that the internal structure of the mobile is secured with strong security layers. The DA Auth File currently works as a decoder, which tells the flashing tool which sections of the mobile can be accessed and how. It is a file based on a specific algorithm that only works for that model or series, and if the correct file is not present, the mobile can become even more damaged.
When Huawei Y6II LYO-L02 Mobile gets messages like "Invalid Preloader" or "Device not match with scatter file", it is usually due to an incompatible firmware or protection lock. Such advanced boot-level issues are impossible to fix without a DA Auth File. The DA file allows changes to the internal system by bypassing the flashing process, even if the mobile's bootloader is completely locked. It is not just software, but the starting point for the entire recovery process.