Can you share some specific stories from the Satcharita about people being cured of illnesses by Baba's Udi?

Yes, Chapter 33 includes several powerful examples of Udi's healing properties, particularly in a footnote by R. Hari Sitaram Dixit. One story concerns the daughter of Khimji Lalji Joshi, who was so weak from a prolonged illness that her limbs were like twigs and she had to be carried. After Sai Baba applied Udi to her and blessed her, she began walking on her own within a few days. Another instance involves a friend of Dixit who couldn't sleep for eight days and found no relief from medicine. After taking the Udi for just one night, he slept soundly. A similar case is mentioned of a child from Bandra who had been unable to sleep for two months, but began sleeping normally from the very night he was taken for Baba's Darshan in Shirdi.