How to Repair and Fix IMEI baseband on Oppo A3S CPH1803 ?

Oppo A3S (Model: CPH1803) launched in July 2018. The phone came out of the box with Android 8.1 Oreo powered by Snapdragon 450 chipset. Here we’ve shared the guide the way to repair and fix IMEI number on Oppo A3S.

The IMEI number may be a unique identification or a serial number for all mobiles that comes out-of-the-box. It’s 15 digits IMEI number that identifies GSM phones thanks to SIM swapping. Therefore, an IMEI can track a phone’s hardware round the world. Keep in mind that each one the IMEI numbers are very unique for every and each mobile device. But if just in case , your device has null or invalid IMEI, you must  fix it.
If your device doesn’t have the IMEI (International Mobile Equipment Identity) number, the carrier network won’t work on your device also . The same thing happens with each dual SIM or higher SIM slot devices also. Each and each SIM slot are registered with a singular IMEI number and may be checked by typing *#06# on the dial pad of your phone and it’ll automatically show up the number.

Oppo A3S: Device Overview

Oppo A3s The phone comes with a 6.20-inch touchscreen display with a resolution of 720×1520 pixels and an aspect ratio of 19:9. Oppo A3s is powered by a 1.8GHz octa-core Qualcomm Snapdragon 450 processor. It comes with 2GB of RAM. The Oppo A3s runs Android 8.1 Oreo and is powered by a 4230mAh battery.

Steps to Repair and Fix IMEI number on Oppo A3S CPH1803

Some times due to software issues or after flashing any custom firmware, your device may get corrupted or bricked. Similarly, the device IMEI number can also become invalid or removed which is quite unfortunate. Here we will share the QCN Rebuilder tool guide to restore IMEI number on the Oppo A3S device. QCN Rebuilder is a free tool to restore IMEI on any Oppo or Redmi devices.

Now, let’s check out the download links and requirements below.

Download Files:




  • This guide and QCN file are for the Oppo A3S model only.
  • Your device should be charged up to 50% at least.
  • A PC/Laptop and a USB cable are required.
  • Keep a full backup of the device data before doing anything.
  • Enable USB Debugging. Check the video guide.
  • Download all the files and tools from above.

IMEI Rebuilding and Restore Guide

  • After downloading, install and run the QCN Rebuilder tool on your PC.
  • Click on Open file and select the Oppo A3S QCN file.
  • Now, replace the IMEI with the original IMEI number.
  • Click on Rebuild.
  • Next, connect your phone to a PC using a USB cable.
  • Open dial pad on your device and type this code *#*#717717#*#* or you can try this method to enable diagnostic mode.
  • If the above code doesn’t work, use CMD on your PC by following the commands below.
adb shell
setprop sys.usb.config rndis,diag,adb
  • Then run the QPST tool on your computer.
  • Click on the Restore tab > select the rebuilt QCN file > click on Restore.
  • You’re done.

That’s it, guys. We hope you’ve found this guide useful for your Oppo A3S. If you’re facing any issues, feel free to ask in the comments below.