keerthi vasan
New member
This is the first build that has fully trashed a phone for me. I am in an endless reboot loop, followed by the frowny face, followed by gears churning and a reboot, etc. I've had builds that needed a reset to run right, but never got stuck in the upgrade cycle.
I have a 640xl. When I get home I will try to recover back to 8.1, upgrade on a clean install and see what happens. I am seeing a wider set of experiences here. This build seems rather sensitive to the state of the phone when upgrading, since I am not detecting a pattern based on device. Some low end devices upgraded fine according to comments. Some older ones did. Others have had severe problems.
At least cloud backups make blowing the OS away and starting over fairly lossless (other than time looking at turning gears).
I had the same issue with the build 10166 on my Lumia 520. With this spinning gear and sad face reboot loop, I think recovery tool will be of no use here. The tool simply wouldn't recognize my phone. Had to flash the ROM on to the phone. Hope this helps you if you get into the same dead end.