See the video tutorial below or @ https://youtu.be/ni5sTRvcr-I
One rare problem you could encounter on an MTK (e.g Tecno, Gionee, Oppson, Infinix, Micromax etc) Android phone is for the phone to display things upside down. Sometimes, this could occur when changing from portrait to landscape view. This issue is usually as a result of flashing an incompatible ROM / backup; to be precise, an incompatible build.prop or kernel. Although this is not a common occurrence, its not exactly a very serious issue so don't panic. Fixing this issue requires you to replace the build.prop (as the case may be).
How to fix
Some methods you could apply in fixing this issue are:
1. Edit build.prop orientation setting
Install ROM Toolbox Lite (root required). In system/build.prop, look for a line like this (if not present then insert it)
Ensure the value is set to 0
2. Replace build.prop content
Install ROM Toolbox Lite on the phone (root required) and open the system/build.prop file in ROM toolbox. If its written in strange characters, overwrite all its content with that you copied from the build.prop of another phone of the same model.
3. Flash system.img (Android)
Flash another system.img (Android) using SP flash tool @ https://forum.hovatek.com/thread-159.html . Flash the entire ROM if it persists
4. Create Flashable zip
Extract the build.prop (from system.img) from a working phone then copy into a flashable zip and flash in recovery mode.
How to create a flashable zip
The easiest method to create a flashable zip is to use a flashable zip creator like Zip me or any good one you can get.
Alternatively, you can download the already created flashable zip file in the attachment below and use 7zip to drag n drop any file(s) you wish to import into it.
5. Screen Orientation setting Mobile Apps
Consider using Set Orientation, Display orientator or Ultimate Rotation Control