Regardless of whether the DFU port documentation is technically wrong or the author misdiagnosed the root cause, the real failure here is that macOS silently spent an hour "installing" an update, then rolled back without any actionable error message. No "hey, try a different port." No diagnostic log surfaced to the user. Just a vague "some updates could not be installed" notification with a "Details" button that shows no details. Apple knows which port each device is connected to. Apple knows which port is the DFU port. If there's a known incompatibility with external disk updates on that port, the OS should refuse to start the update with a clear message, not waste an hour of the user's time and silently fail. This is the kind of UX regression that erodes trust in the platform, especially for power users who are exactly the audience booting from external disks.