Did Sai Baba actually attend Dev's Udyapan ceremony after promising to do so?

Yes, Sai Baba did attend Dev's Udyapan ceremony, though not in the form Dev expected. Chapter 40 explains that Baba came in the guise of a Sanyasi, accompanied by two other individuals. Dev, failing to recognize him, felt disappointed and wrote a letter to Jog complaining that Baba had broken his promise. Baba later clarified the situation to Jog, stating, "I said I would come with two others, and I went with two others." This reveals that Baba kept his word, but his presence was veiled by Maya, testing Dev's perception. When Dev learned the truth, he was overcome with remorse for his lack of recognition.