Apparatus and method for managing data in a hybrid data storage device. The device has a first non-volatile memory (NVM) of solid state memory cells arranged into a first set of garbage collection units (GCUs), and a second NVM as a rotatable data recording medium arranged into a second set of GCUs each comprising a plurality of shingled magnetic recording tracks. A control circuit combines a first group of logical block units (LBUs) stored in the first set of GCUs with a second group of LBUs stored in the second set of GCUs to form a combined group of LBUs arranged in sequential order by logical address. The control circuit streams the combined group of LBUs to a zone of shingled magnetic recording tracks in a selected one of the second set of GCUs. A combined media translation map identifies physical addresses in both the first and second NVMs.