# Uploading to ESP8266 - "A device attached to the system is not functioning" **URL:** \ **Category:** IDE 2.x\ **Created:** [December 22, 2024, 12:50am UTC](https://forum.arduino.cc/t/uploading-to-esp8266-a-device-attached-to-the-system-is-not-functioning/1334635 "2024-12-22T00:50:52Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![SabatM](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/sabatm/32/1127224_2.png) [@SabatM](https://forum.arduino.cc/u/SabatM)\ **Post date:** [December 22, 2024, 12:50am UTC](https://forum.arduino.cc/t/uploading-to-esp8266-a-device-attached-to-the-system-is-not-functioning/1334635/1 "2024-12-22T00:50:52Z")
Hi guys, idk why the hell this could happen, but neither of my computers can upload to an ESP thru the esptool.py, which gives out an error, stating: `could not open port 'COM5': PermissionError(13, 'A device attached to the system is not functioning.', None, 31)`. Tried reinstalling drivers, downgrading them to a 2023 version, none helped. (it's the CH340 serial chip), also tried uploading to Generic ESP8266, D1 mini (clone) and a Generic ESP32 C3. None worked. Port selection also correct, as an ESP8266 is displayed on boards list when connected, and only one single port is opened when i connect it on my laptop. Any ideas? ---
**Author:** ![ptillisch](https://avatars.discourse-cdn.com/v4/letter/p/ad7895/32.png) [@ptillisch](https://forum.arduino.cc/u/ptillisch)\ **Post date:** [December 22, 2024, 1:29am UTC](https://forum.arduino.cc/t/uploading-to-esp8266-a-device-attached-to-the-system-is-not-functioning/1334635/2 "2024-12-22T01:29:37Z")
Hi @SabatM. > [@SabatM](#): > > Tried reinstalling drivers, downgrading them to a 2023 version, none helped. I think you were on the right track, but you just didn't install an old enough version of the driver. This "`PermissionError(13, 'A device attached to the system is not functioning.', None, 31)`" error can occur when uploading to the boards that use specific batches of the [WCH CH340 USB chip](http://www.wch-ic.com/products/CH340.html). The problem only occurs when using the versions of the CH340 driver from 2023 and after. The affected users have reported that doing a "roll back" to an older version of the driver from 2022 was an effective workaround. You can give that a try. I'll provide instructions you can follow to do that: 1. Click the following link to download the previous version of the driver from the chip manufacturer's website: [https://www.wch-ic.com/downloads/file/65.html?time=2023-03-16%2022:57:59](https://www.wch-ic.com/downloads/file/65.html?time=2023-03-16%2022:57:59) 2. Wait for the download to finish. 3. Run the downloaded `CH341SER.EXE` file. 4. A " **User Account Control**" dialog may now appear asking " **Do you want to allow this app to make changes to your device?**". Click the " **Yes**" button. 5. A "**DriverSetup(X64)**" dialog will open. Click the " **INSTALL**" button in the dialog. 6. Wait for the driver installation to finish, as indicated by the appearance of a " **Driver install success!**" dialog. 7. Click the " **OK**" button in the " **Driver install success!**" dialog. The dialog will close. 8. Click the **X** icon at the top right of the "**DriverSetup(X64)**" dialog The dialog will close. 9. Close Arduino IDE if it is running. 10. Connect the Arduino board to your computer with a USB cable. 11. Open the [Windows **Device Manager**](https://support.microsoft.com/en-us/windows/open-device-manager-a7f2db46-faaf-24f0-8b7b-9e4a6032fc8c). 12. Select **View \> Devices by type** from the **Device Manager** menus. 13. Open the " **View**" menu. 14. If there is a **✓** to the left of the " **Show hidden devices**" menu item, click on " **Show hidden devices**" to disable it. 15. Open the "**Ports (COM & LPT)**" section of the **Device Manager** tree. 16. You should see a port identified as "**USB-SERIAL CH340 (COM_n_)**" under the "**Ports (COM & LPT)**" section (where "COM_n_" is some serial port e.g., COM4). Double click on that item. The "**USB-SERIAL CH340 (COM_n_) Properties**" dialog will open. 17. Select the " **Driver**" tab of the "**USB-SERIAL CH340 (COM_n_) Properties**" dialog. 18. You will see a " **Roll Back Driver**" button in the dialog. If it is not clickable, perform the following instructions: 1. Click the " **Update driver**" button. An "**Update Drivers Device - USB-SERIAL CH340 (COM_n_)**" dialog will open. 2. Click on " **Search automatically for drivers**" in the "**Update Drivers Device - USB-SERIAL CH340 (COM_n_)**" dialog. 3. You should now see the driver installation wizard update the driver. Wait for the update to finish, as indicated by the message " **Windows has successfully updated your drivers**" in the dialog. ❗ It is possible you will instead see the message " **The best drivers are already installed**". If so, please stop following the instructions here and reply on the forum thread to let me know. I'll provide alternative instructions you can follow. 4. Click the " **Close**" button in the "**Update Drivers Device - USB-SERIAL CH340 (COM_n_)**" dialog. The dialog will close. 19. Click the " **Roll Back Driver**" button in the "**USB-SERIAL CH340 (COM_n_) Properties**" dialog. The " **Driver Package rollback**" dialog will open. 20. Click the radio button next to " **My apps don't work with this driver**" in the " **Driver Package rollback**" dialog . 21. Click the " **Yes**" button. The " **Driver Package rollback**" dialog will close. 22. Click the " **Close**" button in the "**USB-SERIAL CH340 (COM_n_) Properties**" dialog. Now start Arduino IDE again and repeat whatever you were doing before when you encountered that error before. Hopefully this time you will not encounter that "`PermissionError(13, 'A device attached to the system is not functioning.', None, 31)`" error during the sketch upload. ---
**Author:** ![SabatM](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/sabatm/32/1127224_2.png) [@SabatM](https://forum.arduino.cc/u/SabatM)\ **Post date:** [December 22, 2024, 1:36am UTC](https://forum.arduino.cc/t/uploading-to-esp8266-a-device-attached-to-the-system-is-not-functioning/1334635/3 "2024-12-22T01:36:16Z")
Just when you wrote that, i found a post on a forum that had 2014 drivers - it works! Thanks for making me sure to go for the older ones. Have a nice day! 😃 ---
**Author:** ![ptillisch](https://avatars.discourse-cdn.com/v4/letter/p/ad7895/32.png) [@ptillisch](https://forum.arduino.cc/u/ptillisch)\ **Post date:** [December 22, 2024, 1:42am UTC](https://forum.arduino.cc/t/uploading-to-esp8266-a-device-attached-to-the-system-is-not-functioning/1334635/4 "2024-12-22T01:42:05Z")
You are welcome. I'm glad it is working now. For the benefit of anyone else with the same problem who finds this forum topic through their research, I'll add a note that, even though I'm sure the 2014 driver will work, installing such an old version is not required. The last compatible driver version is `3.7.2022.01`, which is the version you get from following the instructions I provided. The incompatibility was introduced in the next version of the driver after that: `3.8.2023.2`. Regards, Per ---
**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\ **Post date:** [June 20, 2025, 1:42am UTC](https://forum.arduino.cc/t/uploading-to-esp8266-a-device-attached-to-the-system-is-not-functioning/1334635/5 "2025-06-20T01:42:14Z")
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