I have tried several times on our A/C, which had the version 10.7 and 10.8, but never succeeded. Did anyone know about this?
The steps are shown as following:
Flight Management Computer
This is not a hidden page, but it is the way into them. You can bring up this OFFSET page either from RTE or INIT/REF INDEX.
1. Have this page displayed on both CDU's.
2. Enter any offset but do not execute.
3. Simultaneously press ERASE on both CDU's.