A.download the MTK flash tool and driver
First download the MTK flash tool: https://spflashtools.com/wp-content/uploads/SP_Flash_Tool_v5.1844_Win.zip

And  MTK USB VCOM drivers:

MediaTek USB VCOM drivers:

https://spflashtool.com/download/MediaTek_USB_VCOM_drivers.zip

Or

https://spflashtool.com/download/Driver_Auto_Installer_v1.1236.00.zip

B.download the firmware
Download  your device firmware from device official website. Unzip the firmware package.

C.install MTK driver

https://www.youtube.com/watch?v=0LhcafpJ2J0

D.Use MTK flash tool to upgrade the firmware
Open SPFLASHTOOL EXE and Load the Scatter file ( Click Scatter Loading).

Click on “DOWNLOAD” button on top ( not the tab), If it asks click on “yes”

Switch off your pad,and connect the pad to your computer via USB cable.

It is done and MTK flash Tool will do the rest.

After the tool prompted with a green circle. congrats you have successfully flash your pad with MTK Flash Tool.

https://www.youtube.com/watch?v=80sCEc9Stnk