Rear bicycle derailleur does not shift up (source code)

= Rear bicycle derailleur does not shift up

Full range achieved, going from fastest to slowest works (downshift), but going from slowest to next slowest (upshift) fails. Limits are good, B-tension screw didn't help
* https://bicycles.stackexchange.com/questions/66811/rear-derailleur-does-not-downshift-properly-shifts-up-smoothly likely good question but with wrong up vs down terminology