The normal tutorial dev mode (after recovery mode) doesn’t seem to do anything. After a lot of trial and error, I think AP/CPU ttyUSB1 is disabled in software on production devices.
Some basic CCD functionality is accessible by default: read-only access to the EC console, read-write access to the AP console, and a few basic Cr50 console commands. Note that while Cr50 has read-write access to the AP console by default, the AP console itself is disabled for production devices.
ccd testlab enable might do something.