your blms are intialized at (by default) 128 then they're 'trimmed' based on measurements from closed loop, so if it's not going into closed loop, it'll be locked at 128.

your ecm is smart enough to know that an o2 stuck at 450mv can't be reading correctly yet, so it's not entering closed loop. if you drove around for long enough, it would certainly set an o2 error code or something...