I was going through the Commentary on Matthew and found a reading for Mark that only appears in Secret Mark:
Ἐπεὶ δὲ Μᾶρκος καὶ Λου κᾶς κατὰ τινὰς μὲν τὴν αὐτὴν ἱστορίαν ἐκτίθενται κατὰ δὲ τινὰς ἑτέραν παραπλησίαν, ἄξιόν γε καὶ τὰ τούτων ἰδεῖν. καὶ πρῶτόν γε κα τανοητέον τὴν κατὰ τὸν Μᾶρκον, οὕ τως ἀναγράψαντα τὰ κατὰ τὸν τό πον· «καὶ ἔρχεται εἰς Ἱεριχώ. καὶ ἐκπορευομένου αὐτοῦ ἐκεῖθεν καὶ τῶν μαθητῶν αὐτοῦ καὶ ὄχλου ἱκανοῦ, ἰδοὺ ὁ υἱὸς Τιμαίου Βαρτιμαῖος τυ φλὸς» καὶ τὰ ἑξῆς, ἕως τοῦ «καὶ ἠκο λούθει αὐτῷ ἐν τῇ ὁδῷ»[Comm Matt 16:12]
Yet as far as I can see all texts of Mark read:
Καὶ ἔρχονται εἰς Ἰεριχώ
there are no other citations of:
καὶ ἔρχεται εἰς Ἱεριχώ
And it's not as if this is an isolated example. Origen consistently cites Mark this way. Again:
καὶ εἴποι τις ἂν κατὰ τὸν μυστικὸν λόγον ὅτι πρῶτόν ἐστι τὸ τοῦ Λουκᾶ, δεύτερον δὲ τὸ τοῦ Μάρ κου, καὶ τρίτον τὸ τοῦ Ματθαίου. πρῶτον γὰρ δεῖ ἐγγίσαι τῇ Ἱεριχώ, εἶτα εἰσελθεῖν εἰς αὐτήν, καὶ <μετὰ ταῦτα δὲ> ἐκπορευθῆναι ἀπ' αὐτῆς. ἀνέγραψε τοίνυν ὁ μὲν Λουκᾶς τὸ «ἐγένετο ἐν τῷ ἐγγίζειν αὐτὸν εἰς Ἱε ριχώ», ὁ δὲ Μᾶρκος· «καὶ ἔρχεται εἰς Ἱεριχώ, καὶ ἐκπορευομένου αὐτοῦ ἐκεῖθεν», ὁ δὲ Ματθαῖος οὔτε τὸ ἐγγίζειν τῇ Ἱεριχὼ ἀνέγραψεν οὔτε ὅτι ἔρχεται εἰς Ἱεριχώ, ἀλλὰ μόνον ὅτι ἐκπορευομένων αὐτῶν ἀπὸ Ἱεριχώ, ἠκολούθησεν αὐτῷ ὄχλος πολύς. [Comm Matt 16.13]
The Letter to Theodore reads:
And after the words, "And he comes into Jericho," the secret Gospel adds only, "And the sister of the youth whom Jesus loved and his mother and Salome were there, and Jesus did not receive them."
Μετὰ δὲ τὸ καὶ ἔρχεται εἰς Ἱεριχὼ ἐπάγει μόνον, καὶ ἦ σαν ἐκεῖ ἡ ἀδελφὴ τοῦ νεανίσκου, ὃν ἠγάπα αὐτὸν ὁ Ἰησοῦς, καὶ ἡ μήτηρ αὐτοῦ
καὶ Σαλώμη, καὶ οὐκ ἀπεδέξατο αὐτὰς ὁ Ἰησοῦς.
So what now? Morton Smith knew this and didn't add this to his meticulous study of the discovery? They didn't have searchable PDF's in the 1960s and 1970s. Smith didn't know therefore Smith didn't forge Letter to Theodore.
“Finally, from so little sleeping and so much reading, his brain dried up and he went completely out of his mind.”
― Miguel de Cervantes Saavedra, Don Quixote