This guide will come in handy for Mediatek (MTK) and Spreadtrum (SPD) Android device users who suddenly end up with a totally dead device that won't power up or respond to buttons (but makes a sound when connected to a PC) as a result of intentionally or unintentionally interrupting the flash or backup process. Interruption could be triggered by shaking / unplugging the USB cord or even an error popup / prompt in the tool you're using.
What you should know about flashing or backing up MTK and SPD Android devices generally is that you shouldn't interrupt the process. If you do, the phone could go off and not come on at all. You might get the "USB device not recognized" error on further attempts. If somehow, the process got interrupted and you now have a totally dead phone on your hands, don't panic. All you need to do is connect the phone to a computer (via a USB cord) or power source and leave it to charge for some time. It could take between hours to even days but once the phone is revived, your battery could read as low as 1% . just leave it to keep charging before powering it up.
Tips to speed up reviving your phone
- Disconnect / take out the battery > Connect the phone to a charger without battery inside > Slot in the battery while the phone is still connected to the charger > Press the power button
- You could keep pressing the Volume up + Power button while charging
- You could remove and boost the battery using a desktop / external charger then resume internal charging.
- Uninstall then re-install MTK preloader vcom drivers using this guide @ https://forum.hovatek.com/thread-440.html or SCI drivers for SPD @ https://forum.hovatek.com/thread-827.html