# ttyUSB device not detected after BalenaOS update **URL:** \ **Category:** balenaOS\ **Created:** [July 30, 2019, 3:04pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658 "2019-07-30T15:04:07Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![krix](https://avatars.discourse-cdn.com/v4/letter/k/b9bd4f/32.png) [@krix](https://forums.balena.io/u/krix)\ **Post date:** [July 30, 2019, 3:04pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/1 "2019-07-30T15:04:07Z")
I upgraded two devices from balenaOS 2.29.0+rev1 to balenaOS 2.38.3+rev4 and now my USB serial adapter is no longer detected. A USB device is detected but the USB tree does no longer show the ttyUSB endpoint. Did you remove any drivers? Changes to the udev system? When I plugin the USB device on a device with the old BalenaOS, dmesg says: > [22067.664660] usb 1-7: new full-speed USB device number 7 using xhci\_hcd > [22067.791853] ch341 1-7:1.0: ch341-uart converter detected > [22067.792125] usb 1-7: ch341-uart converter now attached to ttyUSB1 But when I plugin the USB device on a device with the new BalenaOS, dmesg says: > [966.292273] usb 1-7: new full-speed USB device number 5 using xhci\_hcd And I can’t downgrade the BalenaOS! Ouchh! So do I have to backup the persistent data, reinstall, and restore persistent data, transfer all Balena settings from the old to the new device and delete the old device and … ??? ---
**Author:** ![zrzka](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/zrzka/32/1612_2.png) [@zrzka](https://forums.balena.io/u/zrzka)\ **Post date:** [July 30, 2019, 3:30pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/3 "2019-07-30T15:30:48Z")
Hi, I’m not aware of any change that should cause this. Can you please do the following: - unplug your serial USB adapter, - boot 2.29.0+rev1, - once fully booted, plug the serial USB adapter, - share the `dmesg` output with us. Also what device it is? Yes, there’s no support for the balenaOS downgrade. It’s documented [here](https://www.balena.io/docs/reference/OS/updates/update-process/): > **Note:** Once a successful host OS update has been made, it is not possible to roll back to a previous OS version. Yes, you can do it in this way. Backup persistent data, reinstall the old OS and transfer device specific settings to the new device. ---
**Author:** ![zrzka](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/zrzka/32/1612_2.png) [@zrzka](https://forums.balena.io/u/zrzka)\ **Post date:** [July 30, 2019, 3:33pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/4 "2019-07-30T15:33:25Z")
Thanks for the `dmesg` output! What device it is? ---
**Author:** ![krix](https://avatars.discourse-cdn.com/v4/letter/k/b9bd4f/32.png) [@krix](https://forums.balena.io/u/krix)\ **Post date:** [July 30, 2019, 3:48pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/6 "2019-07-30T15:48:13Z")
The label says: USB-SC09-FX USB to RS422 ADAPTER FRO MELSELC FX PLC AMSAMOTION ---
**Author:** ![zrzka](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/zrzka/32/1612_2.png) [@zrzka](https://forums.balena.io/u/zrzka)\ **Post date:** [July 30, 2019, 3:49pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/7 "2019-07-30T15:49:43Z")
Thanks for this information. Also, can you share the device type you’re using? Not the USB dongle, but if the main device is RPi 3, Intel NUC, Odroid, … Thanks! ---
**Author:** ![krix](https://avatars.discourse-cdn.com/v4/letter/k/b9bd4f/32.png) [@krix](https://forums.balena.io/u/krix)\ **Post date:** [July 30, 2019, 3:53pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/8 "2019-07-30T15:53:26Z")
Sure, sorry for not having that included: Intel NUC ---
**Author:** ![zrzka](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/zrzka/32/1612_2.png) [@zrzka](https://forums.balena.io/u/zrzka)\ **Post date:** [July 30, 2019, 3:59pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/9 "2019-07-30T15:59:17Z")
Don’t be sorry, that’s okay. I shared this info with developers and will come back when I’ll have more info from them. ---
**Author:** ![zrzka](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/zrzka/32/1612_2.png) [@zrzka](https://forums.balena.io/u/zrzka)\ **Post date:** [July 30, 2019, 4:32pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/10 "2019-07-30T16:32:35Z")
Just FYI - asked developers and they’re pretty busy right now. We will have an answer for you, but not sure when. ---
**Author:** ![floion](https://avatars.discourse-cdn.com/v4/letter/f/45deac/32.png) [@floion](https://forums.balena.io/u/floion)\ **Post date:** [July 31, 2019, 10:06am UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/13 "2019-07-31T10:06:34Z")
Hi. This should be solved by [https://github.com/balena-os/balena-intel/pull/236](https://github.com/balena-os/balena-intel/pull/236) ---
**Author:** ![krix](https://avatars.discourse-cdn.com/v4/letter/k/b9bd4f/32.png) [@krix](https://forums.balena.io/u/krix)\ **Post date:** [July 31, 2019, 11:54am UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/15 "2019-07-31T11:54:20Z")
Thx, is there any forecast on when this will be included in a release? ---
**Author:** ![hedss](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/hedss/32/210_2.png) [@hedss](https://forums.balena.io/u/hedss)\ **Post date:** [July 31, 2019, 12:18pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/16 "2019-07-31T12:18:02Z")
Hi again, Our OS release cycles are usually approximately every couple of weeks, so whilst I can’t guarantee it, I’d expect this to be within a fortnight. Best regards, Heds ---
**Author:** ![krix](https://avatars.discourse-cdn.com/v4/letter/k/b9bd4f/32.png) [@krix](https://forums.balena.io/u/krix)\ **Post date:** [August 5, 2019, 12:26pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/18 "2019-08-05T12:26:10Z")
Update: I have a confession to make… It seems that the issue with this kernel module cannot be blamed on the Balena folks. It turns out that our system worked with balenaOS 2.29.0+rev1 only because we ourselves had compiled the kernel module for our USB device. So when we updated to balenaOS 2.38.3+rev4, the compiled module did no longer match the kernel. And I wrongly assumed the balenaOS 2.38.3+rev4 had a regression that broke our system. Sorry about that, and thanks for the support. ---
**Author:** ![agherzan](https://avatars.discourse-cdn.com/v4/letter/a/e95f7d/32.png) [@agherzan](https://forums.balena.io/u/agherzan)\ **Post date:** [August 5, 2019, 12:30pm UTC](https://forums.balena.io/t/ttyusb-device-not-detected-after-balenaos-update/22658/19 "2019-08-05T12:30:22Z")
Hi. We are glad that you found the issue. That is the most important thing. We are here for any other questions. In the meanwhile, enjoy our platform.