Egypt did not display perfectly linear development of religious thought patterns.
In regards to Osiris, his symbols (crook and flail,
https://en.wikipedia.org/wiki/Crook_and_flail ) represented what, today, is called the "neolithic package" of "crops and domesticated animals". And in particular, Osiris was famed for introducing barley into Egypt. Barley belongs in the "neolithic package".
In Heliopolitan (Ennead) cosmology, it is said that Osiris took over Egypt from the primitive "goose god", Geb. (Notably, a goose is not part of what, today, is called the neolithic package.)
The ancient Egyptians somehow convinced themselves that Osiris's "barley" (and the neolithic package of domesticated crops and animals) had originated in Egypt. For example, Egyptian myths claimed that Osiris left Isis in charge of Egypt -- while Osiris toured around the world, spreading a neolithic lifestyle around the world.
But this simple-minded Egyptian theme about Osiris started being shaken to its roots when artisans (from across the Levant) were imported to work on Egyptian king Amenemhet III's huge construction projects.
At about that time of importing foreign laborers, a "Syrian homeland of natural-growing barley" would have started to make a mark on Egyptian consciousness. Not only does barley grow wild near Syria -- but also, barley is called by a word that sounds like Osir in Semitic languages (which are spoken in a wide region around Syria).
Apparently, understanding that a natural homeland for barley had been in-or-near Syria rocked the foundations of Egypt's Osiris religion. From a chronological standpoint, this set the stage for Egypt's Second Intermediate Period -- when it became acceptable in the Nile Delta to believe that Osiris and his brother Set had originated outside Egypt (i.e. near Syria). Some such viewpoint was held among people whom Egypt called Hyksos.
After the Hyksos were driven out of Egypt -- Set became regarded as an evil being, but Osiris religion was revived in Egypt.
Then another innovation occurred in Egyptian religious outlooks (to counterbalance northern influences). In the 18th dynasty, a primitive Egyptian deity Min (and Thebes's god Amon) became identified with a pinnacle at Gebel Barkal, in the far south of Nubia.
http://www.jebelbarkal.org/