...the only reliable solution is to flash the full firmware through . To do that, you need three components:
Downloading and installing Firehose on your Oppo A3s (CPH1803) can help resolve software-related issues and unbrick your device. However, be cautious when using Firehose, as flashing firmware can potentially brick your device if not done correctly. Always verify the authenticity of the Firehose package and follow the installation instructions carefully. If you are unsure about the process, consider seeking help from a professional or Oppo support. download firehose oppo a3s cph1803
: It acts as a bridge for tools like QFIL (Qualcomm Flash Image Loader) or Unlock Tool to write firmware partitions to the internal EMMC storage. be cautious when using Firehose