Compass: External field (at least) not updated after reboot

While updating dozens of Here4s I found that the Setup / Mandatory Hardware / Compass screen is not updating the table's "External" field. For example, this is the view after moving some items around in the table and we see the "external" column is all unchecked.

Then I push the "reboot" button and we see nothing has changed

Then finally I switch away (by pushing the "Config" menu item) and switch back to the compass screen and we see they are checked.

Start in the Setup / Mandatory Hardware / Compass screen and reproduce the issue by changing compass items, pressing Reboot, then switching to Config and back. Trace why the External column refreshes only after leaving and re-entering the screen; done means the table updates immediately after reboot without navigating away.

Written by the indexing model from the issue text.