So I wanted to downgrade my Lumia 1020 from WP 8.1 to 8.

Unfortunately the phone is not recognized on the PC (tried Windows 10 Enterprise, Windows 8 and Windows 7).

I suspect Windows Phone 8.1 is the issue. 90% search results for this issue happened to be using Windows Phone 8.1.

Both PC device manager shows @Unknown USB Device (Device Descriptor request Failed)".

Here are the things I tried:

  1. Tried different cables (including what came with Lumia 1020)
  2. Tried installing other software for driver support, such as Microsoft phone app, Windows Device Recovery tool and few others.
  3. Have read almost all links related to "Lumia WP 8.1 USB issues" from answers.microsoft.com and reddit.com. Tried all those steps and still it can't recognize the PC. Installed winusb.inf and wpdmtp.inf file.

Also tried soft reboot, hard reboot even while connecting to PC. Rebooting PC while phone is connected.

Update: Just installed Windows 7 and when I plug the phone, it shows as "unknown device". I'm pretty sure it's not a port issue since many users have the same issue.

Any methods to downgrade without connecting to PC OR any way to make it detectable on PC?

I'll try and visit service center next week and have them test the port.

  • Yeah, same issue here. on the cable that i use to connect is don't have an issue since it work well with other phone. So im pretty sure its related with drivers things. very bad. and by the way, i use a windows 10 laptop with latest update version 1803 build 17134.165; it showing 'unknown device' on 'other device' section, but nothing change even when i try install so called 'lumia 1020 driver' – Iwan Junifanto Aug 5 at 11:36

This happens. What you can do is download the driver booster software from their site. It has incredible database of drivers including those of old lumias. However if you still can't connect, there maybe a hardware issue

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