Data Migration: Unload/load of GENERATED ALWAYS TIMESTAMP
I'm not sure you can alter a column with that clause. The knowledge center suggests that this syntax should do it,

ALTER TABLE CFFOLIO.FOLIO ALTER COLUMN "TIMESTAMP"
SET GENERATED ALWAYS FOR EACH ROW ON UPDATE AS ROW CHANGE TIMESTAMP;


but it does not appear to work.

One option would be to use LOAD. E.g. https://www.ibm.com/developerworks/community/blogs/IMSupport/entry/DB2_Preserving_existing_timestamp_data_when_moving_tables_which_contain_a_ROW_CHANGE_TIMESTAMP_column?lang=en