This is device take customer for flashing then first i try to flash with HTC desire 816 [MT6592] then sp flash tool show error then i check again firmware site then understand in this device two different cpu first of MT6592 or MT6582 so please first check device cpu after try to flashing because if not success then understand different cpu in device be carefully.
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. Download tested firmware or flash tool from above link (if link not working just write down comment on below comment box i will soon fix it)
2. Extract to both file into desktop or as you like path (must installed winrar software in your computer or laptop)
4. Click on Scatter-loading button and choose MT6582_Android_scatter.txt file from LWDMC220.127.116.11.1T25A1115_M028 folder
7. Wait until driver install, if driver installed in your computer or laptop then downloading automatically starting into device