I have done a stock ROM backup for a brand new Tecno S3 smartphone: the download link will be provided at the bottom of this post.
1. Download MTK Droid Root & Tools v2.5.1 here
2. Windows PC
3. Rooted MediaTek device. (you can root with eroot if the device has android 4.0 and above)
1. First thing is to root your MediaTek Android device
2. Second step would be to download and install the MTK Droid tools
3. Now connect your rooted phone to the computer and let it be detected by the MTK tools
4. Note the colour at the bottom of the droid tool. It has to be green. if its not, click on Root located at the bottom right of the MTK page.
5. It will prompt you, OK it and let it gain su access.
6. Click on root, backup and recovery tab and click on the big Backup button
7. Wait for it to begin the backup process which can take up to 10 – 15 minutes depending on your computer speed.
8. After backup is created, it will ask you if you want to pack it to a zipped format. Click yes
9. Wait a while for the packing to finish
10. When its finish, you can navigate to the folder where the backup is stored for use at anytime you please.