Downgrade unlocked AT&T 640 from 10 to 8.1

[Windows Central Question]

I have been trying to revert my lumia 640 from WP10 to WP8.1 which i can do using Windows Device recovery tool since it has that version on the server to put on it. I go to do it and right when it gets to the installing part it restarts the phone and says it failed to install. I have tried to reset my phone and then do it, tried multiple microusb cables, tried second computer, usb3 and usb2 ports, windows desktop 10 and 8.1 and nothing seems to change. i tried to go to the windows store and get it reverted but they said it would cost me $50 to do which is more than the phone and i should be able to do it from my computer on a program Microsoft provides. if anyone can help i would appreciate it!

 

[abhishek singh21]

I have been trying to revert my lumia 640 from WP10 to WP8.1 which i can do using Windows Device recovery tool since it has that version on the server to put on it. I go to do it and right when it gets to the installing part it restarts the phone and says it failed to install. I have tried to reset my phone and then do it, tried multiple microusb cables, tried second computer, usb3 and usb2 ports, windows desktop 10 and 8.1 and nothing seems to change. i tried to go to the windows store and get it reverted but they said it would cost me $50 to do which is more than the phone and i should be able to do it from my computer on a program Microsoft provides. if anyone can help i would appreciate it!

Hi and welcome to widows central

try reinstalling the WDRT by first completely removing it and rebooting the system then installing it again with current version.

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[zarcha]

I tried this as well and it changed nothing. Seems to just restart right when it starts to install when in flash mode.

 

[zarcha]

Sorry this was my post. I tried uninstalling as well just in case it was a bad install and restarted in case it needed to do something in the background afterwards.

 

[Chintan Gohel]

Sorry this was my post. I tried uninstalling as well just in case it was a bad install and restarted in case it needed to do something in the background afterwards.

what about trying the option that say my phone wasn't detected?

And is your phone working okay or it has no working OS now?