After updating controller firmware from 2021.0.5 to 2022.0.3, the controller project and included HMI can remain operational while HMI access fails with 503 Service Temporarily Unavailable. The reported recovery is a Type 1 reset followed by project reinstallation.
Identify the Firmware-Update Failure
The reported controller uses an installed SD card and a project that includes an HMI. The failure appeared after the firmware transition, even though the project otherwise worked correctly.
| Check | Observed result |
|---|---|
| Firmware transition | 2021.0.5 to 2022.0.3 |
| Controller project | Works correctly |
| Direct HMI page |
https://192.168.1.10/ehmi/hmiapp.html returns 503 |
| Cockpit HMI access | Does not work |
Separate the Confirmed Issue from Unknowns
The evidence identifies this behavior as a known issue under active investigation. It does not identify the internal root cause, additional affected firmware versions, or the exact HMI service responsible. Do not treat the 503 response alone as proof of an addressing, certificate, SD-card, or project-logic fault.
Recover HMI Access
Use the reported workaround in this order. The available evidence does not define what a Type 1 reset preserves or removes, so confirm the reset's device-specific consequences and ensure the project is available for reinstallation before proceeding.
- Perform a Type 1 reset on the controller.
- Reinstall the project, including its HMI content.
This workaround resolved the reported failure, but the evidence does not establish it as a permanent firmware correction.
Verify the Recovery
After project reinstallation, open https://192.168.1.10/ehmi/hmiapp.html and confirm that the page no longer returns 503 Service Temporarily Unavailable. Then access the HMI through the cockpit and verify that both access paths work.
FAQ
Why does the HMI return 503 after updating to 2022.0.3?
The failure is identified as a known issue associated with the reported update from 2021.0.5 to 2022.0.3. The evidence does not provide the internal root cause.
How do I restore the HMI after the firmware update?
Perform a Type 1 reset and then reinstall the project. Verify recovery through both the direct HMI URL and the cockpit.
Does a working controller project rule out the HMI 503 issue?
No. In the reported case, the project worked correctly while both direct HMI access and cockpit access failed.