Not reachable after firmware update

[theMPstig]

Hey guys,

I made a firmware update yesterday for the zendure support and afterwards the OpenDTU is not reachable in my network any more. Ping answers with a timeout. The update itself did run fully fine and I got the message that the page refreshes itsself after reboot. Any ideas how to troubleshoot?
Thanks

[theMPstig]

A few additional infos: OpenDTU was reachable, but showed 0% output level, so I switched to 100% -> after that system was unreachable. When I look into my router, the system is not connected via WLAN.
Currently I am not at home for the next days so I guess there is nothing I can do at the moment, right? Maybe it switched back to initial and I have to re-connect with OpenDTU initial WLAN?

[schlimmchen]

Hm, that sucks... However, I don't think there is anything you can do remotely if you are unable to force a power-on-reset.

As for the reason: Have you installed the factory.bin using OTA by mistake? Otherwise: This happened to me in the past as well, but very few times only, and has not happened for a long time (roughly a year) now. A power-on reset helped in those cases.

[theMPstig]

Thanks for the answer and no worries. Back on Sunday.

but: I didn’t install the factory bin and as the DTU is on a smart plug I did already a power reset a few times with no success.

But as said: no worries, I just wanted to check if there are any options. Will report back when hopefully repaired.

[Napizaki]

After updating to the latest version 2025.04.17 (a99bf86) from the previous release on my ESP32-S3 USB, I suddenly also have the problem that the OpenDTU is no longer accessible. The Fritzbox shows the DTU as offline. However, it seems that only the WLAN connection is affected - the DTU itself seems to be running (I can see on the PowerMeter that something is being fed in and the feed-in value changes even when the battery is full (FullSolarPassthrough). After a power cycle it works again (for now).
I didn't have this problem before.

After the first outage (where I was not at home), I installed a WiFi socket and created an automation that restarts the DTU as soon as the connection fails. On the diagram below you can see how often the DTU fails.

My parents with an ESP32 (without S3) have no problems with the new firmware.

[Napizaki]

Hello, I have flashed the firmware back again - but the error was still there. It is a hardware defect on the circuit board - exactly as described here:
https://www.amazon.de/gp/customer-reviews/R17RDWY2NJZW3C/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=B0CLD4QKT1

I also bought this exact product. When I press on the chip cover, it works. I've now put a guard clip on it until a replacement has arrived and it works (for now).

There are also many reports that the WLAN works better if you reduce the transmission power of the WLAN:
esphome/issues#6456
Is there any way to set this in the DTU?

[schlimmchen]

We are not working around hardware issues using software.

What you are looking at are cheap Chinese clones (both the module as well as the board). Usually they work just fine, but sometimes they just don't. What always works fine (and which has an authentic ESP32-S3 module rather than a clone) is an OpenDTU Fusion Board 😉

[Napizaki]

You are right, I totally agree.

[theMPstig]

Reporting back: DTU is working again - lost all settings, but I had a backup...