Why is my phone stucked during upddate to windows 10?

[Windows Central Question]

I wanted to update my lumia 820 from windows phone 8.1 to wp 10 but my phone is restarting over and over during the installation.

 

[ven07]

Hard reset the phone and try again

 

[RafaelPowerless]

Hi
My lumia 925 won?t update either.
It keeps turning off and when I turn it back on it shows the upgrading icon and turns off again.
It doesnt?t master reset either. I think i broke it hahaha

 

[Wesley James Holroyd Newman]

The same happens when with my lumia 520 but i cant get the hard reset to work as my phone turns off to fast. How can it be fixed?

 

[ven07]

Guys, there isn't exactly a solution for this. The best you can do, is download the windows phone recovery tool and hope it detects your phone. Flashing might also be an option for you guys, but it requires patience and a lot of research before getting into it