What are the main topics covered in Chapter 42 of the Sai Satcharitra based on the provided text?

As presented in the source material, Chapter 42 of the Sai Satcharitra serves as a pivotal chapter. It begins by referencing miracles from the previous chapter, such as a portrait being protected from water and a devotee being guided in a dream, to illustrate the Guru's power. The text then declares its main purpose: to describe Sai's nature and, most significantly, to provide a detailed account of Sai Baba leaving his physical body. As described in Chapter 42, remembering the Sadguru's feet is said to dissolve all obstacles and sorrows. The chapter culminates by meticulously documenting the specific date and time of Baba's Mahasamadhi, including the Shaka year, lunar day, and other calendar details.