How To Flash M-HORSE S15 Official Stock Firmware Flash File with Research Download/UpgradeDownload Tool
Download and Install Spreadtrum USB Driver on your Computer.
Download and extract Spreadtrum Upgrade Tool on your computer. After extracting, you will be able to see the following files Now, open UpgradeDownload.exe.
connect your Android device to the computer (make sure your device is switched off).
Once your Smartphone is connected successfully to the computer, click on the Load Packed Button and add the .pac file (stock ROM which comes as .pac).
Once you have successfully added the.Pac file in Spreadtrum Upgrade Tool, click on the Start Downloading button to begin the flashing.
During the flashing process, your device will restart automatically. Once flashing is completed, you will be able to see the Green Passed Message in Spreadtrum Upgrade Tool.
Now you have successfully flashed your Android Device using Spreadtrum Upgrade Tool. Once your Android Device is successfully restarted, Go to Settings > About Phone > Check firmware.