# HELP! Lumia 640 Device Not Recognized - Device Descriptor Request Failed



## x_orange90_x (Jan 9, 2016)

So lately I've been having more and more issues with my Lumia 640, such as random reboots, data switching, and slow downs. I decided that since I haven't preformed a hard reset since about 2 builds ago, it was time for it. I went ahead and reset, and everything appeared to be working better. It was when I plugged my phone into the laptop to dev unlock and deploy tools that I ran into trouble. As soon as I plug it in, I get the device connected sound followed by USB Device Not Recognized error, a Phone charging slowly message on the phone, and then a device unplugged sound from the laptop. I tried it on my desktop and get the exact same results. Both my computers are running Windows 10, and my 640 is on latest 10586 build.

I've tried everything I could think of/find online including
-Soft reset the device while plugged 
-Using different Usb cable
-Uninstalling the device (read below)
-Rebooting the PC and letting it turn the phone on with it
-Uninstall all Usb Root Hubs
Unplug PC power cord/battery and Usb devices and wait 10-15min
-Developer Mode on/off
-Hard Reset phone again

I really don't know what else to do. When I plug it in and get the not recognized error, it's a Descriptor Request Failed, and then the device disconnects. In Device Manager it shows under Universal Serial Bus (as an Unknown device with the Descriptor Request Failed next to it) until it disconnects itself, then it disappears. Using Show Hidden Devices and a command to enable showing every device ever connected (plugged in or not), I see it show but it's greyed out and it's properties page says it's disconnected. While showing all hidden devices, I uninstalled the phone under Portable Devices as it used to work, along with my wife's phone. 

Nothing I've done has gotten me anywhere. It just connects with the error and immediately disconnects. It used to work with both the laptop and desktop before I hard reset. The only thing i believe could be causing it was the fact that before the reset my phone was being faked as a Lumia 1520. But I've uninstalled that in the hidden devices of Device Manger. 

Any help would be greatly appreciated. As it stands, I can't developer unlock, deploy tools, or even copy my pictures!

Edit- just tried plugging it into 2 other computers with WinXP (. I know it's not supported), and also get the device not recognized and charging slowly. So... Either the firmware/os git messed up, or the Usb jack is messed up.


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## animesh_shah (Jan 14, 2016)

I have also have same problem. If you find the solution. Pls let me know. problem is you cannot roll back to 8.1 without connection to PC

---------- Post added at 02:54 PM ---------- Previous post was at 01:56 PM ----------

probably this can help
http://mobifaq.com/why-can-t-i-connect-my-lumia-640xl-to-my-laptop/t9893/


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## anubis23 (Jan 18, 2016)

Does device charge properly using AC? Based your trouble shooting so far it seems like it be the Usb port acting up.. I am assuming the Usb cables were 6ft and under? Did you flash any non stock rom to the phone? And what do you mean faked as a 1520? If the phone acts weird while charging it definitely could be the phones Usb port. If not you can put the phone in flash mode and use thor2 list device connection list to see if and how long the phone is being detected by windows.


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## augustinionut (Jan 19, 2016)

OP, you have interopunlocked phone with  FS acces?


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## x_orange90_x (Jan 21, 2016)

augustinionut said:


> OP, you have interopunlocked phone with  FS acces?

Click to collapse



 as a matter of fact yes, to both!



anubis23 said:


> Does device charge properly using AC? Based your trouble shooting so far it seems like it be the Usb port acting up.. I am assuming the Usb cables were 6ft and under? Did you flash any non stock rom to the phone? And what do you mean faked as a 1520? If the phone acts weird while charging it definitely could be the phones Usb port. If not you can put the phone in flash mode and use thor2 list device connection list to see if and how long the phone is being detected by windows.

Click to collapse



 charging is perfectly fine. I also suspected the Usb port, but after an online chat with Cricket Support, they assured me it was a software issue. 



animesh_shah said:


> I have also have same problem. If you find the solution. Pls let me know. problem is you cannot roll back to 8.1 without connection to PC
> 
> ---------- Post added at 02:54 PM ---------- Previous post was at 01:56 PM ----------
> 
> ...

Click to collapse



 the thing is, I couldn't even restore to 8.1 with my issue. The phone would not stay connected long enough to be identified by the OS let alone the Recovery Tool.



However, I have good news. I did finally solve the problem.  When I had realized that connecting the phone while in the boot loader got it to detect and install as Lumia BootMgr, I opened up the Recovery Tool and sure enough it was detected. I let it start downloading the ROM, and about 1/2 way through I heard the device disconnected sound and thought oh great this isn't going to work either. However, the download kept going, and when it finished I clicked the start install button, but it gave an error saying the device was not detected. So with the phone still plugged in, I preformed a soft reset and continued holding Volume down to boot back into the boot loader. When I came to the ! screen and the phone was detected again as Lumia BootMgr, I clicked Retry in the Recovery Tool and it actually copied over the ROM, which thankfully is a very quick process. 

Once 8.1 had finished setting up the phone was detected and installed perfectly on the computer. Last night I updated back to W10 and it's still detecting without an issue.  I'm for sure not enabling the Full Filesystem Access hack again. Before this problem started I was already tired of waiting up to 30 minutes at a time for it to connect. Only reason I did it was to copy the custom HOSTS mod file to block ads, which I'd love to do again, but it's just not worth it.


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## augustinionut (Jan 21, 2016)

So, if FS acces, enter device manager on pc, disable windows phone, enable windows phone.... wait a minute...voila


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## x_orange90_x (Jan 21, 2016)

augustinionut said:


> So, if FS acces, enter device manager on pc, disable windows phone, enable windows phone.... wait a minute...voila

Click to collapse



Are you referring to the problem I was having? If you are, then reread my OP. You'll see that Device Manager would not even display the phone because the phone would immediately disconnect after the USB Device Not Recognized error popped up. There was simply nothing to disable, or enable for that matter. 

If your saying to disable and enable AFTER applying the FS access hack to affect the detection time, then please, elaborate on that.


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## augustinionut (Jan 21, 2016)

Erase driver, reinstall driver, try with another pc, sell the phone....


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## titi66200 (Jan 21, 2016)

@x_orange90_x

http://forum.xda-developers.com/win...de-filesystem-access-sftp-windows-10-t3185766


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## x_orange90_x (Jan 22, 2016)

augustinionut said:


> Erase driver, reinstall driver, try with another pc, sell the phone....

Click to collapse



 you obviously did not reread the OP.. I tried all of those with the exception of the last with no sucess.


And I think you've missed my point entirely.. I solved the issue already. Hopefully the other member that posted in here with the same problem can fix it by following what I did.


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## augustinionut (Jan 22, 2016)

You right.. disable full fs access....


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## Ari2K3 (Nov 28, 2020)

You still active Mr. Orange


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