flash tool download address:
here is the stock firmware downloard address for cubot gt90:
the steps is also in the folder
1.Open the flash tool in the package.
2.Choose files by button”Scatter file”. You should choose the file named”MT6572_Android_scatter.txt” here.
3.Click “Start all”.
4.Connect the phone with your PC,wait for several minutes.
If it does not work,please try to take off the battery before connect PC and try again.