28.2.1.4 Spare Row
As data needs to be preserved between row erasures, a single FLASH row is kept unused to act as destination for copied data when a write request is made to an already full row. When the write request is made, any logical pages of data in the full row that need to be preserved are written to the spare row along with the new (updated) logical page data, before the old row is erased and marked as the new spare.