After a successful OTA upload the web panel polled the device by
fetching "/" and waiting for a 200 OK response. This approach
is fundamentally broken when the new firmware contains a freshly
generated self-signed certificate (e.g. from a clean CI build):
- The browser rejects the TLS handshake with a certificate error
(MOZILLA_PKIX_ERROR_SELF_SIGNED_CERT in Firefox; other browsers
report different error names but behave identically). The fetch()
call throws a generic TypeError — the same type thrown for any other
network failure such as a refused or timed-out connection. Browsers
intentionally provide no way to distinguish a cert rejection from a
plain connectivity failure, so the catch block cannot tell whether
the device is up-but-cert-changed or simply not yet online.
- Switching to an explicit http:// URL to sidestep TLS is not an
option: the web panel is served over HTTPS, and browsers block
active mixed content (fetch/XHR to HTTP) unconditionally from an
HTTPS origin.
Because no network-based probe can reliably detect device readiness
under these constraints without changing how the certificate is
generated, replace the polling loop with a simple 10-second countdown
timer that unconditionally redirects to the login page. The device
is typically back online within ~7 seconds, so the 10-second wait
provides a reasonable safety margin.
Valentin V. Bartenev
59f6df50c5