This tutorial tested by me without any error just you have to following this tutorial step by step first check your device battery must charged battery up to 80% second check your device key because here for detection need boot key so must working well your device battery of volume up third must good quality micro usb cable some cables available in market but not detected so here need must quality usb cable this device is MTK cpu so need sp flash tool for flash.
This flash file tested by me without any error working well, you can use this flash file when your device hang on logo problem, restarting problem, security lock problem, password lock problem, pattern lock problem etc software related problem and you can use this tutorial without any box and this is free for all who know about software in mobile, impotent for flashing first must check your micro usb cable if not good then you can't flash it so check micro usb cable second check your device battery that is impotent for flashing if your device battery low so stop your device between flash so this is impotent for flash, before you flash save your data like contact, photos, videos etc because this is factory flash file so you can't save after full flash so must remember all are impotent notes.
1. First download tested firmware or flash tool from above link (if link not working just leave your comment on below comment box)
2. Extract to desktop or as you like path (must installed winrar software in your computer or laptop)
4. Click on Scatter-loading button and choose MT6572_scatter_lv73_A269i_U_MPV1_A21_131031.txt file from firmware folder
6. Press and hold Volume up button and insert usb cable (must working well of device key or micro usb cable)
7. Wait until driver install, if driver installed in your computer or laptop then downloading automatically start into device