System update fails "Could not open path to sync"

General Discussions
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1

System update fails. When config was previously working. With “Could not open path to sync”

We created our own pi image using mender-convert to increase the root disk size. Then created a system artifact using mender-artifact. And successfully deployed it to a new device with the raw pi image from the mender-convert step. This was on 15-Aug-2025, I believe that the mender-update version was 5.0.1.

But now it is not working. I am trying to deploy the same system artifact to a new device with the raw pi image mender-update version 5.0.3 (installed using the copy paste commands given in the ‘connect new device’ tab on the devices dashboard) I get this log output. looks like the path is uninitialized.

“timestamp”:“2025-11-11T14:27:28.877306Z”,“level”:“info”,“message”:“Running Mender client 5.0.3”}
{“timestamp”:“2025-11-11T14:27:28.877617Z”,“level”:“info”,“message”:“Deployment with ID cea1e339-2f95-4484-a75c-a1f073092312 started.”}
{“timestamp”:“2025-11-11T14:27:28.878769Z”,“level”:“info”,“message”:“Sending status update to server”}
{“timestamp”:“2025-11-11T14:27:29.913904Z”,“level”:“info”,“message”:“Installing artifact…”}
{“timestamp”:“2025-11-11T14:27:29.923150Z”,“level”:“error”,“message”:“No such file or directory: Could not open path to sync: ߠ\n^B^@^@^@^@/mender/modules/v3/payloads/0000/tree/version”}
{“timestamp”:“2025-11-11T14:27:29.923740Z”,“level”:“error”,“message”:"Operation canceled: GET https://c271964d41749feb10da762816c952ee.r2.cloudflarestorage.com/mender-artifact-storage-prod-h>
{“timestamp”:“2025-11-11T14:27:29.944763Z”,“level”:“info”,“message”:“Sending status update to server”}
{“timestamp”:“2025-11-11T14:27:30.688438Z”,“level”:“error”,“message”:"Could not send deployment status: Bad response error: Got unexpected response 400 from logs API: invalid character '\x0>
{“timestamp”:“2025-11-11T14:27:30.688629Z”,“level”:“info”,“message”:“Retrying status update after 60 seconds”}
{“timestamp”:“2025-11-11T14:28:30.688825Z”,“level”:“info”,“message”:“Sending status update to server”}

Repeated lines….

{“timestamp”:“2025-11-11T15:03:46.859720Z”,“level”:“error”,“message”:"Could not send deployment status: Bad response error: Got unexpected response 400 from logs API: invalid character '\x0>
{“timestamp”:“2025-11-11T15:03:46.859934Z”,“level”:“error”,“message”:“Giving up on sending status updates to server: Tried maximum number of times: Exponential backoff”}
{“timestamp”:“2025-11-11T15:03:46.863945Z”,“level”:“info”,“message”:“Deployment with ID cea1e339-2f95-4484-a75c-a1f073092312 finished with status: Failure”}

2

Hi @paul.m,

While I have no obvious solution - what happens if you install a really simple artifact, possibly just a file? You can create one on the fly on Hosted Mender, just upload a text file instead of an artifact, and it will guide you through the creation of a simple file artifact which you can deploy right afterwards.

Greetz,
Josef

3

Hi Josef,

Thank you for your response.

I tried this, and I get the same error message {“timestamp”:“2025-11-11T14:27:29.923150Z”,“level”:“error”,“message”:“No such file or directory: Could not open path to sync: ߠ\n^B^@^@^@^@/mender/modules/v3/payloads/0000/tree/version”}

Best regards,

Paul

4

Hi @paul.m,

Is this a board you have at hand? Respectively, is only that one affected, or multiple ones? What happens if you rebuild the image?

Greetz,
Josef

5

Hi Josef,

I have another device that is working, it has the same hardware, root filesystem has same checksum (as shown in the software tab on mender hub). The only difference that I can see in the inventory is that the one that is working is running mender client version 5.0.1 and the one that is not is running 5.0.3. Do you know the best way to downgrade to 5.0.1?

In the mean time I will try from scratch with new hardware.

Best regards,

Paul

6

Hi Josef,

I have tried again with new hardware (new rpi and SD card), installing the same image, then setting up mender client by copy pasting the commands given through hosted mender, then deploying a hello world text file as you suggested. And I get the same issue, but with a different string of random characters. So it does not appear to be hardware related.

level":“error”,“message”:“No such file or directory: Could not open path to sync: ���^A^@^@^@^@/mender/modules/v3/payloads/0000/tree/version”}

Best Regards,

Paul

7

Hi @paul.m,

Something is really weird here, and it’s the only report that I know about so far. :frowning:
You can try to downgrade by specifically setting MENDER_CLIENT_VERSION, as seen here: mender-convert/configs/mender_convert_config at 25ea12e7663eb75a4cf783b18c202585138cb86b · mendersoftware/mender-convert · GitHub

Greetz,
Josef

8

Hi Josef,

I have it working now.

I flashed another SD card with the same image, then changed the /etc/mender/mender.conf to add the hosted mender server and the tenant token. Rebooted and accepted the request. Now I can deploy again. So it seems that the ‘connect new device‘ script to setup the latest mender client was the issue after all. I will create a new image with mender convert that has the tenant token and serverURL built in so that I don’t have to keep copy pasting it in.

Thank you.

Best regards,

Paul

9

Hi @paul.m,

Glad to hear! I’ll check back with the devs if there might be a problem with the copy-paste instructions in onboarding. But great that you can proceed!

Greetz,
Josef

10

Hi @paul.m ,

Good that you found a solution.

However I still suspect another issue. These strange path prefixes like:

ߠ\n^B^@^@^@^@/mender

makes me suspect an old issue that we had with armhf packages. Are you using 32 bit based OS image from Raspberry Pi OS?

We don’t support these anymore with the new releases, starting from mender-update 5.0.2.

Maybe I am off, but I just wanted to rule this out.

Lluís

11

Hi Lluís,

OK, thank you for this.

Yes we based the Mender converted image from the example raspberry pi 4 image from the mender docs website: Prepare a Raspberry Pi device | Mender documentation

Which was 32bit raspios bookworm armhf lite.

So will there be an issue if we continue to use this OS with the mender-client 5.0.1? Will mender-client 5.0.1 continue to work for deployments going forward?

Would there be any issue deploying a 64bit system update with mender client 5.0.3 to a device that is running 32bit OS with Mender client 5.0.1?

Paul