I heard a story about a girl who couldn't walk and was cured by Baba. Can you tell me the details of this from the Satcharita?

Yes, this story is recounted in a footnote in Chapter 33 of the Shri Sai Satcharita, as noted by R. Hari Sitaram Dixit. It concerns the daughter of Khimji Lalji Joshi, who was part of a Punjab regiment. His daughter was so ill and weak that her limbs had become like twigs and she could not walk. She had to be carried and seated near Maharaj in Shirdi. Sai Baba applied Udi to her and blessed her. Within just two to four days, she began to walk on her own. When she still had trouble getting up and sitting down, she complained to Baba, who then gave her a fruit to eat. From that moment on, that difficulty was also removed, showcasing a complete cure.