Onyx Boox Poke5P User Manual page 27

Sync settings
You can sync reading progress
and data across devices via
Onyx Cloud. The feature is on by
default. If you do not want to sync
your reading data of all documents, you can turn this
feature off.
If you do not want to sync the reading data of some
documents, long press their book covers to go to Sync
Settings, and turn their sync off individually.
Note: Currently, only reading data can be synced to the
Cloud. The source document cannot be synced to the
Cloud. You need to add documents to the same path on
different devices for the sync.