The commands do not all go to the same place
LG Universal Control configures a supported external set-top box for Magic Remote operation. TV volume can work even when box navigation has not been configured, because those actions have different targets.
Identify the desired box, its HDMI input and the missing command. Keep the original box remote available to verify that its own controls work.
Check the integrated setup
LG says supported webOS generations can attempt automatic setup and also provides a manual route through on-screen instructions. Follow the exact TV model’s guidance and the supported device identity rather than inventing a configuration code.
Test directions, OK, Back and the viewing actions that matter. Record each command independently. One working power or volume action does not establish the remaining command set.
Keep the useful fallback
If an essential box function is unavailable, retain its original remote. A partial integrated setup can still be convenient without being described as full one-remote control.
A precise support request lists the configured box identity and the commands that fail. It does not blame the programme source for a control path that never reaches the box.
Questions answered
Does TV volume working prove Universal Control is complete?
No. It does not establish external-box navigation.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.